The age of a and b are in the ratio of 7:5. Ten years the ratio of their age will be 9:7.find their present age?
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The easy way to do this is by using a "multiplier"
let x = the multiplier
then
7x = A's present age
and
5x = B's present age
Adding 10 yrs to their age produces a ratio of 9:7, there
7x+10/5x+10=9/7
cross multiply
7(7x+10) = 9(5x+10)
49x + 70 = 45x + 90
49x - 45x = 90 - 70
4x = 20
x = 20/4
x = 5 is the multiplier
Their present ages
A: 5(7) = 35 years
B: 5(5) = 25 years
let x = the multiplier
then
7x = A's present age
and
5x = B's present age
Adding 10 yrs to their age produces a ratio of 9:7, there
7x+10/5x+10=9/7
cross multiply
7(7x+10) = 9(5x+10)
49x + 70 = 45x + 90
49x - 45x = 90 - 70
4x = 20
x = 20/4
x = 5 is the multiplier
Their present ages
A: 5(7) = 35 years
B: 5(5) = 25 years
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