Question

The numerator of a fraction is 15 less than twice its denominator. If the numerator is increased by 5 and the denominator is increased by 7, the new fraction will be equal to 2/3. What is the original fraction?

Answer 1

Answer:

  7/11

Step-by-step explanation:

Let d represent the original denominator. Then the original numerator is ...

  2d-15

The new numerator is ...

  (2d-15) +5

and the new denominator is ...

  d+7

The ratio of these is 2/3, so we have ...

  $\dfrac{2d-15+5}{d+7}=\dfrac{2}{3}\\\\3(2d-10)=2(d+7) \quad\text{cross multiply}\\\\4d=44 \quad\text{add 30-2d}\\\\d=11\\\\2d-15=2(11)-15=7$

The original fraction is 7/11.