Coffee A and coffee B are mixed in the ratio x：y by weight. A costs $50/kg and B costs $40/kg. If the cost of A is increased by 10% while that of B is decreased by 15%, the cost of the mixture per kg remains unchanged.
Find x :y
A. 2 : 3
B. 5 : 6
C. 6 : 5
D. 3 : 2
E. 55 : 34
1 Answer | Add Yours
According to the given data we can derive the following equations.
Cost of coffee mixture `= 50x+40y ----(1)`
It is given that the cost of A is increased by 10% while that of B is decreased by 15%.
Cost of Coffee A `= 50+50/100xx10 = 55`
Cost of coffee B `= 40-40/100xx15 = 34`
Since the cost of coffee remains same;
Cost of coffee mixture `= 55x+34y ----(2)`
(1) = (2)
`6y = 5x`
`6/5 = x/y`
`x:y = 6:5`
So the ratio of x:y = 6:5 and the correct answer is at C)
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