Question

the sum of the ages of a and b is 60 years. 10 years ago a was thrice as old as B was. find their present age.

Answer 1

Here is your answer

According to the given conditions

a + b = 60

And

a - 10 = 3(b - 10)
a - 10 = 3b - 30
a - 3b = - 20

Hence lets subtract the equations

a + b = 60
a - 3b = -20

4b = 80
b = 80/4
b = 20 Years

Hence the age of b is 20 years so the present age of a will be

a + b. = 60
a = 60 - b
a = 60 - 20
a = 40

Hence the age of a is 40 years

Hope it helps

Answer 2

suppose the age of 'a' is X years...
and the age of 'b' is Y years...
°.° X+Y = 60 (1) ×3
before 10 years ago...
(X-10)= 3(Y-10)
X-10 = 3Y-30
X-3Y = -30+10
X-3Y= -20 (2)
now adding eq(1) & eq(2)..
X+Y= 60 (1)×3
X- 3Y = -20
.. 3X+3Y=180
X-3Y= -20
---------------------
4X = 160
X = 40Years
now put the value of X in eq(1)
X+Y = 60
40+Y = 60
Y = 60-40
Y = 20.
SO the ages of a is 40..
and ages of b is 20 years
hope this will help u...