i think 32 is the answer.

see 20*10 = 200

22*12 = 264

64/2= 32

the sum of the ages of 3 persons is 150 yrs .10yrs ago their ages were in the ratio 7:8:9.their present ages are

a).(45,50,55)                                                                                                                           b).(40,60,50)

c).(35,45,70)                                                                                                                            d).none.

Ten years ago, their ages were in the ratio 7:8:9, so you can assume their ages 10 years ago to be 7x, 8x and 9x respectively.

As of now, their ages would be 7x + 10, 8x + 10 and 9x + 10

The sum of these ages is 150, so:
7x + 10 + 8x + 10 + 9x + 10 = 150
or, 24x + 30 = 150
or, 24x = 150 - 30 = 120
or, x = 120/24 = 5

So their present ages are 7*5 + 10, 8*5 + 10 and 9*5 + 10
i.e. 45, 50 and 55 (a)

32

thanks.........................................................