A container holds a combination of two liquids A and B in a 7:5 ratio. The ratio of A and B becomes 7:9 when 9 litres of mixture are taken out and the can is filled with B. How many litres of liquid A did the can originally hold?
A. 10
B. 20
C. 21
D. 25
Answer:C
A container holds a combination of two liquids A and B in a 7:5 ratio. The ratio of A and B becomes 7:9 when 9 litres of mixture are taken out and the can is filled with B. How many litres of liquid A did the can originally hold?
A. 10 B. 20 C. 21 D. 25
Explanation: Assume the can contains 7x and 5x of mixes A and B at the start.7x - 7/12 x 9 litres = 7x - 21/4 litres Quantity of A in mixture left = 7x - 7/12 x 9 litres.Quantity of B remaining in the combination = 5x - 5/12 x 9 litres = 5x - 15/4 litre=7x - 21/4 /5x -15 + 9 = 7/9 = 28x - 21/20x + 21 = 7/9 = 252x - 189 = 140x + 147 = 112x = 336 = x = 3.As a result, the container held 21 litres of A.