Question

Ages of a and b are in the ratio 5:7.8 years ago their ages were in the ratio 7:13.Find their present ages.​​​​​​​​​​​​

Answer 1

let the present age of a =5x

then the present age of b =7x

simillarly ,8years ago if age of a =7y

then 8 years ago age of b =13y

A.T.C. ...

7y + 8 =5x ........(1)

13y +8 = 7x.............(2)

multiply (1) by7 and (2) by 5....we get

49y +56 = 35x..........(3)

65y + 40 =35x............(4)

subtract (4) from (3) ..we get:

-16y + 16 =0

16y=16

y=1

put y=1 in (1)

7y+8 =5x

7+8 =5x

15=5x

x=3

present age of a =5x=15 years

present age of b =7x=21 years