Question

three years hence, a man's age will be three times his brothers age,and the sum of present age is 18.find their present age​

Answer 1

Older brother = 15

Younger brother = 3

Explanation:

Let the present age of the older brother = x

Let the present age of the younger brother = y

x + 3 = 3(y+ 3) Remove the brackets

x + 3 = 3y +9

x + y = 18 Solve for x

y = 18 - x Put this value into the top equation

x + 3 = 3(18 - x) + 9

x + 3 = 54 - 3x + 9

x + 3 = 63 - 3x Add 3x to both sides

x + 3x + 3 = 63 Subtract 3 from both sides. Combine the xs

4x = 63 - 3

4x = 60 Divide by 4

4x/4 = 60/4

x = 15

x + y = 18

15 + y = 18

y = 3