Question

a drum of kerosene oil is 3 upon 4 full when 15 litres of oil is drawn out it is 7 upon 12 full find the total capacity of the drum

Answer 1

Let the capacity of drum be x liter
Given,
$\frac{ 3}{4} x - 15 = \frac{7}{12}x \\ ( \frac{3}{4} - \frac{7}{12} )x = 15 \\ \frac{1}{6} x = 15 \\ x = 90 \: \: liter$