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CH-03-001 · Fractions of remainders and reverse capacity

A tank is full. First, 14\frac{1}{4} of its water is used. Then 15\frac{1}{5} of the water remaining is used. Finally, 12\frac{1}{2} of what remains is transferred to containers, giving 660 litres. Work out the original capacity of the tank and how many litres must be added after all three operations to fill it again.

Reverse Fractions of Remainders Booklet p. 19 & p. 53
Method
1) Multiply remaining fractions at each stage
2) Multiply by fraction transferred and equate to given litres
3) Divide to find full capacity
Worked Example (CH-03-001)
1)
Fraction left after the first two uses = 35\frac{3}{5}.
2)
Fraction of the original transferred = 310\frac{3}{10}.
3)
Divide the transferred volume by this fraction.
4)
Capacity 2200 litres.
5)
Water left after all three operations = 660 litres.
6)
Add 1540 litres.
Ans = Capacity 2200 litres; add 1540 litres.