Subject :IMO Class : Class 7
Two numbers are in the ratio 5 : 3. If 10 is subtracted from both the numbers, their ratio changes to 5 : 7. The sum of numbers initially was ______.
A8
B15
C13
D12
Ans 1:
Class : Class 8
Let the initial numbers be x, then 5:3 becomes 5x/3x. then, 5x-10 divided by 3x-10 equals 5x divided by 7x.
so the equation becomes: 7 (5x-10) = 5(3x-10). solve it and you get x=1
Therefore the sum of 5:3 is 8.