Mathematical Operations Questions and Answers

Answer: C

Correct answer: 1

Replacing the words by their symbols gives \( 12 \div 6 - 28 + 3 \times 9 \), and by the usual order \[ 2 - 28 + 27 = \mathbf{1} \]

Answer: A

Correct answer: A + C = B + D

From \( A+B = 2C \) we get \( B = 2C-A \), and from \( C+D = 2A \) we get \( D = 2A-C \). Adding those, \[ B + D = (2C-A) + (2A-C) = A + C \] so A + C = B + D.

Answer: A

Correct answer: 30 – 6 + 5 × 4 ÷ 2 = 27.

Substituting in this option gives \[ 30 \div 6 \times 5 + 4 - 2. \] Taking the divide and multiply first: \( 30\div6 = 5 \), \( 5\times5 = 25 \). Then \( 25 + 4 - 2 = 27 \), which matches the stated value. The other three fail once their symbols are replaced.

Answer: B

Correct answer: 3

The symbols stand for division and multiplication: \( 3 \div 4 \times 8 = 6 \) and \( 9 \times 4 \div 3 = 12 \), so # is ÷ and % is ×. Then \[ 12 \times 6 \div 24 = \mathbf{3} \]

Answer: C

Correct answer: 210

Substituting gives \[ 12 \times 90 \div 5 - 9 + 3. \] Multiplication and division first, left to right: \( 12\times90 = 1080 \), \( 1080\div5 = 216 \). Then \( 216 - 9 + 3 = 210 \). Stopping at 216, before the last two terms are applied, gives the second option offered.

Answer: B

Correct answer: 2

Replacing the symbols gives \( 5 - 10 + 21 \times 5 \div 15 \), and by the usual order \[ 5 - 10 + 7 = \mathbf{2} \]

Answer: B

Correct answer: 2400

\( 49^2 = 2401 \), and 49.001 differs from 49 by so little that the square is still about 2401. To the nearest figure offered that is 2400.

Answer: A

Let the least value of the prize = Rs. x

Then the next value of the prize is x+30 , x+60, x+90, ....x+240.

Given total amount of cash prizes = Rs.1890

--> x + (x+30) + (x+60) + (x+90) + ....+ (x+240) = 1890

--> 9x + (30 + 60 + 90 + 120 + 150 + 180 + 210 + 240) = 1890

--> 9x + 30(1 + 2 + 3 + 4....+ 8) = 1890

--> 9x + 30(36) = 1890

--> 9x = 810 --> x=90

Hence the least value of the prize x=90

Answer: C

Correct answer: 3 > 2 < 4 x 8 + 4 < 2

This item cannot be worked as it stands: the stem breaks off part way through the list of definitions, so only the meaning of the first symbol survives. Without the full set of substitutions the four expressions cannot be evaluated or compared.

Answer: A

Correct answer: 153

Substituting gives \[ 14 \times 10 + 42 \div 2 - 8 = 140 + 21 - 8 = 153. \] Both the multiplication and the division are completed before anything is added or subtracted, which is what keeps the two products separate rather than running them into one another.