Machine-translated by Google. Questions are authored in English.
Top

Discussion

A fraction is such that when 3/4 is added to it, we get 1/3. What is the fraction?

  • A.2/1
  • B.4/7
  • C.-5/12
  • D.5/12

Answer: C

The fraction is -5/12.

Let the fraction be x. Then

\[ \begin{aligned} x + \frac{3}{4} &= \frac{1}{3} \\ x &= \frac{1}{3} - \frac{3}{4} = \frac{4 - 9}{12} = -\frac{5}{12} \end{aligned} \]

Check: \(-5/12 + 9/12 = 4/12 = 1/3\). The positive 5/12 comes from dropping the minus sign, and would give 14/12 when 3/4 is added.

The other two options fail the same check: \(2/1 + 3/4 = 11/4\) and \(4/7 + 3/4 = 37/28\), both greater than 1, while the required sum 1/3 is less than 3/4, so the fraction must be negative.

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.