Multiple choice

A tin of oil was $\displaystyle \frac{4}{5}$ full. When six bottles of oil were taken out and four bottles of oil were poured in it was $\displaystyle \frac{3}{4}$ full. How many bottles of oil did the tin contain initially?

  1. 16

  2. 40

  3. 32

  4. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let x be the total capacity. Initially, the tin has 0.8x. After removing 6 and adding 4, it has 0.8x - 2 = 0.75x. Thus, 0.05x = 2, so x = 40.