Question

a is
four times as old as B 10 years ago a was 10 times as B find the present age of B

Answer 1

let at present
age of B = x years
age of A=4x years
10 years ago
age of B =(x-10) years
age of A =(4x-10) years
age of A = 10*age of B
4x-10=10(x-10)
4x-10=10x-100
100-10=10x-4x
90=6x
90/6=x
15=x
therefore
x=15
at present
age of B=x=15 years
age of A=4x=4×15=60 years

Answer 2

a-4x
b-x
10 years ago-
a-10(4x-4)
b=x-4
40x-40=x-4
39x=36
x=0.9