Question

The age of lena and heena are in the ratio 7:5 , ten yrs hence , the ratio of their ages will be 9:7. Their present age.

Answer 1

Let lena's age=x
and heena's age=y
According to question
x/y=7/5
cross multiply
we get      ,5x=7y
now              y=5x/7
also,according to ques,
x+10/y+10=9/7
cross multiply
(x+10)7=(y+10)9
7x+70=(5x/7 +10)9
7x+70=45x/7+90
7x-45x/7=90-70
49x-45x/7=20
4x/7=20
4x=140
x=35
now ,we have y=5x/7
                           =5*35/7
                           =25
 

Answer 2

let lena's age be 7x and heena's age be 5x.
after 10 years:
leena's age will be 7x + 10 and heena's age will be 5x + 10.
It is given that , 
(7x+10)/(5x+10) = 9/7
7(7x+10)=9(5x+10)
49x+70=45x+90
49x -45x = 90 - 70
4x = 20
x = 20/4
= 5
therefore, lena's present age is 7x = 7*5 = 35 years and heena's present age is 5x = 5*5 = 25 years.