Answers

2015-04-12T13:17:57+08:00

let 'x' be the age of the boy at present

'y' be the age of his brother at present

--------------------------------------

the boy is 10 years older than his brother

x = 10 + y     ----------equation 1

-------------------------------------

in 4 years, he will be twice as his brother's age

in 4 years, 'x+4' is the boy's age

                 'y+4' is his brother's age

x + 4 = 2(y+4)    -------equation 2

------------------------------------

substitute equation 1 to equation 2

10 + y + 4 = 2(y+4)

10 + y + 4 = 2y + 8

10+4-8 = 2y-y

6 = y

y = 6

----------------------------------

Substitute y = 6 to equation 1

x = 10 + y

x = 10 + 6

x = 16

------------------------

Therefore the age of the boy is 16 and his brother's age is 6

0
2015-04-13T19:33:31+08:00
A boy is ten and his brother will be twice his age in 4 years so it means that in 4 years his brother will be 6 and a boy will be 16.
0