Your Answer : (Not Answered)

Correct Answer : A

The original cost of the treadmill is Rs. 12,500.

Selling at a 6% loss and selling at a 4% gain differ by 10% of the cost price, and that difference is the extra Rs. 1,250.

\[ \begin{aligned} (4\% + 6\%) \times C &= 1250 \\ 0.10\,C &= 1250 \\ C &= 12500 \end{aligned} \]

Check: a 6% loss gives Rs. 11,750 and a 4% gain gives Rs. 13,000, which differ by Rs. 1,250. Note that 11,750 and 13,000 among the options are those two selling prices, not the cost.

Your Answer : (Not Answered)

Correct Answer : B

The line chart gives the numbers of calculators sold by the five shops as 20, 50, 75, 125 and 100. Their sum is 20 + 50 + 75 + 125 + 100 = 370, and the average over the five shops is 370 / 5 = 74. So the answer is 74, option (B). The values 76, 72 and 78 would need totals of 380, 360 and 390, which do not match the chart, and the point of 125 for the fourth shop is the highest while 20 for the first is the lowest.

Your Answer : (Not Answered)

Correct Answer : C

MATHEMATICS has eleven letters, with M, A and T each appearing twice. Its vowels are A, E, A, I and its consonants M, T, H, M, T, C, S.

Treating the four vowels as one block gives eight units, among which M and T each repeat:

\[ \frac{8!}{2!\,2!} = \frac{40320}{4} = 10{,}080 \]

Within the block the four vowels include two A's:

\[ \frac{4!}{2!} = 12 \]

\[ 10{,}080 \times 12 = 120{,}960 \]

Three separate repetitions have to be divided out - the M's and T's among the units, and the A's inside the block.

Your Answer : (Not Answered)

Correct Answer : A

Correct answer: ₹965

The present worth is \[ \text{PW} = \frac{100 \times A}{100 + RT}, \] with \( RT = 8 \times 3 = 24 \). So \[ \text{PW} = \frac{100 \times 1196}{124} = \frac{119600}{124} = 964.52, \] which to the nearest rupee is 965. Checking forwards: 965 at 8% for three years earns about 231.60 in interest, giving 1,196.60 - the small excess being the effect of rounding. The true discount is the remainder, \( 1196 - 965 = 231 \) approximately. The distractor 1,000 is what a reader arrives at by treating the discount as interest on the face value: \( 1196 \times 0.24 = 287 \), leaving about 909, or by rounding carelessly. Applying the formula rather than working backwards from a guess avoids it.

Your Answer : (Not Answered)

Correct Answer : C

FUZZTONE has eight letters with Z appearing twice: vowels U, O, E and consonants F, Z, Z, T, N.

Treat the three vowels as one block, giving six units among which Z repeats:

\[ \frac{6!}{2!} = 360 \]

Within the block the three distinct vowels arrange in

\[ 3! = 6 \text{ ways} \]

\[ 360 \times 6 = 2160 \]

The repeated Z is divided out among the units, but the vowels are all different so no division is needed inside the block.

Your Answer : (Not Answered)

Correct Answer : B

Count forward until the accumulated odd days come back to zero.

\[ 2003:1,\ 2004:2,\ 2005:1,\ 2006:1,\ 2007:1,\ 2008:2,\ 2009:1,\ 2010:1,\ 2011:1,\ 2012:2,\ 2013:1 \]

\[ \text{total} = 14 = 2 \times 7 \quad\Longrightarrow\quad 0 \text{ odd days} \]

So the calendar of 2003 repeats in 2014. Leap years contribute two odd days each, which is why the cycle is 11 years and not 7.

Your Answer : (Not Answered)

Correct Answer : B

A cone has a single apex and a base bounded by a simple closed curve - in the familiar right circular cone, that curve is a circle.

The distinction from a pyramid is exactly the base: a pyramid's base is a polygon, made of straight edges, while a cone's is a smooth closed curve.

A triangle is a plane figure, not a solid, and a dice is a cube with no apex at all.

Your Answer : (Not Answered)

Correct Answer : B

The first train has a half-hour head start.

\[ \text{lead at 8:30} = 90 \times 0.5 = 45 \text{ km} \]

The second closes at \( 120 - 90 = 30 \) km/hr:

\[ t = \frac{45}{30} = 1.5 \text{ h} \]

\[ \text{distance from Kolkata} = 120 \times 1.5 = 180 \text{ km} \]

Checking with the first train: \( 90 \times 2 = 180 \) km in the two hours since 8 pm.

Your Answer : (Not Answered)

Correct Answer : A

Correct answer: physical barriers such as skins and rinds

An intact skin, rind, shell or cuticle is a physical barrier that organisms cannot cross, so the sterile interior remains protected however contaminated the outside. This is why whole fruit keeps far better than cut fruit, why an intact eggshell matters, and why bruising and cutting are the events that start spoilage. The tissue beneath is generally rich in nutrients and water, so nothing else in the option list is holding the organisms back.

Your Answer : (Not Answered)

Correct Answer : A

Replicate tubes are inoculated with measured volumes, the pattern of positive tubes is recorded, and statistical tables convert it into the most probable number per 100 millilitres. It is an estimate with confidence limits rather than a direct count.

Your Answer : (Not Answered)

Correct Answer : D

IgM appears early, so finding it suggests a recent or current infection and can support a diagnosis from one sample. IgG rises later and persists, which is why it is followed across two samples rather than read on its own.

Your Answer : (Not Answered)

Correct Answer : C

Plus-sense RNA reads in the same direction as mRNA, so a ribosome can translate the genome as soon as it reaches the cytoplasm and the naked nucleic acid alone is infectious. Minus-sense RNA reads the opposite way and must first be copied, which is why such viruses carry their own polymerase.

Your Answer : (Not Answered)

Correct Answer : C

Correct answer: the variable region of the heavy chain remains the same but its constant region changes

This is what makes class switching useful: recombination replaces the heavy chain constant region gene while leaving the assembled variable region intact, so the antibody keeps the specificity that was selected for and acquires new effector functions. The light chain is not involved at all.

Your Answer : (Not Answered)

Correct Answer : B

The vitamin is vitamin-E.

Vitamin E (tocopherols) is fat-soluble and occurs in vegetable oils such as wheat germ and sunflower oil. In the NCERT summary of vitamins, its deficiency is associated with increased fragility of red blood cells and muscular weakness.

Vitamin A deficiency causes night blindness and xerophthalmia, vitamin D deficiency causes rickets, vitamin B6 deficiency causes convulsions, and vitamin B12 deficiency causes pernicious anaemia.

Your Answer : (Not Answered)

Correct Answer : B

The ras oncogene acts because ras codes for a GTPase switch protein, which in its mutated form cannot be switched off.

Ras is a small G protein that relays signals from growth factor receptors to the MAP kinase pathway. It is on when bound to GTP and turns itself off by hydrolysing GTP to GDP. Point mutations, commonly at codons 12, 13 or 61, block this hydrolysis, so Ras stays in the GTP-bound state and keeps telling the cell to divide even without a growth signal. Mutant ras is found in many cancers, including about 90 per cent of pancreatic cancers.

An overproduced anti-apoptotic protein describes bcl-2, an overproduced transcription factor describes myc, and a truncated, always-active growth factor receptor describes erbB. None is how ras works.

Your Answer : (Not Answered)

Correct Answer : A

Coat colour genes on the X are expressed from whichever chromosome remains active in each patch of skin. This is why such cats are almost always female. A male would carry only one X and so only one coat colour allele.

Your Answer : (Not Answered)

Correct Answer : D

The statement that is NOT correct is ELISA is used to detect specific DNA sequences directly without antibodies; it is the only one the key marks in this multiple-select question.

ELISA, the enzyme-linked immunosorbent assay, depends on antibodies by definition: an antibody (or antigen) is fixed to a plate, the target binds, and an enzyme-linked antibody produces a coloured or fluorescent signal. It is normally used to detect and quantify proteins and other antigens, not DNA sequences.

The other three statements are correct: Southern blotting detects specific DNA sequences with a labelled probe, Northern blotting detects RNA and so reports expression levels, and Western blotting detects proteins with antibodies.

Your Answer : (Not Answered)

Correct Answer : D

The IUPAC name is 3-ethyl-5-methylheptane.

The longest chain runs from the CH3 at the left through the main chain to the CH3 at the right: seven carbons, so the parent is heptane. Numbering from either end puts the substituents on carbons 3 and 5. When the numbers tie, the substituent cited first in alphabetical order gets the lower number, so ethyl (e) takes 3 and methyl (m) takes 5, and substituents are listed alphabetically.

3-methyl-5-ethylheptane has the right locants but the wrong alphabetical order. The hexane names miscount the longest chain, and names such as 3,5-diethylhexane would describe a different molecule.

Your Answer : (Not Answered)

Correct Answer : E

Benzyl chloride is the most reactive towards S_N1.

An S_N1 reaction goes through a carbocation, so the faster the carbocation forms and the more stable it is, the faster the reaction. Benzyl chloride gives the benzyl cation, which is stabilised by resonance with the benzene ring.

2-Chloropropane gives a secondary carbocation, much less stable. Chloroethane and iodoethane would give primary carbocations and react by S_N2 instead. Chlorobenzene hardly reacts at all, because its C-Cl bond has partial double-bond character.

Your Answer : (Not Answered)

Correct Answer : A

The main ripening hormone is ethylene.

In climacteric fruits such as banana, mango, tomato and apple, ripening is triggered by a burst of ethylene production together with the respiratory climacteric. Ethylene switches on the genes for softening (cell-wall enzymes), colour change (chlorophyll breakdown, carotenoid synthesis), and sugar and aroma production, which is why it is used commercially to ripen fruit.

ABA mainly controls dormancy and stomatal closure, auxin promotes fruit set and growth, and gibberellin promotes fruit enlargement (as in grapes), but none of them is the main ripening hormone.