<PRE><B>Question 982416</B>
The figure is exactly one-quarter full.
 If 7 liters of liquid are added , the vessel will be exactly three-fifths full. What is the total capacity of the vessel? 
: \
let x = total capacity of the vessel
then
{{{1/4}}}x + 7 = {{{3/5}}}x
multiply equation by 20, cancel the denominators, you have:
5x + 20(7) = 4(3x)
140 = 12x - 5x
140 = 7x
x = 140/7
x = 20 liters is total capacity
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:
Check this
{{{1/4}}}(20) + 7 = {{{3/5}}}(20)
5 + 7 = 12</PRE>