A mixture has two liquids A and B in a certain ratio. When 10 litres of B is added to the mixture, the ratio of A and B becomes 13 : 9. When 30 litres of B is added to the mixture, the ratio of A and B becomes 1 : 1. Find the initial ratio.
A mixture has two liquids A and B in a certain ratio. When 10 litres of B is added to the mixture, the ratio of A and B becomes 13 : 9. When 30 litres of B is added to the mixture, the ratio of A and B becomes 1 : 1. Find the initial ratio. Correct Answer 13 : 7
GIVEN :
After adding 10 litres of B is added to the mixture, the ratio of A and B becomes 13 : 9
After adding 30 more litres of B is added to the mixture, the ratio of A and B becomes 1 : 1
FORMULA USED :
Basic concept of mixture and Alligation.
ASSUMPTION :
Let the volumes of A and B be a and b respectively.
CALCULATION :
a/(b + 10) = 13/9
⇒ 9a = 13b + 130
⇒ a/(b + 30) = 1
⇒ a = b + 30
Putting the value of a in the equation, we get
⇒ 9(b + 30) = 13b + 130
⇒ 9b + 270 = 13b + 130
⇒ 140 = 4b
⇒ b = 35
⇒ a = b + 30 = 65
∴ the initial ratio was 65 : 35 = 13 : 7