Question

ten years later A will be twice as old as B and 10 years ago A was twelve times as old as B. what are the present age of A and B ?

Answer 1

let the age ofA be x and B be y 
2(×+10)=Y+10 
2×+20=y+10 
2×-y=-10 ...........(1)×1 

12(×-10)=y-10 
12×-120=y-10 
12×-y=110 ...........(2)×1 

by subtracting equation 1 from 2 ,we get, 

2× - y = -10 
12× - y = 110 
(-) (+) (-) 
____________ 
-10× = -120 
10× = 120 
× = 120/10 
× = 12 
by substituting the value of x in equation 2, we get, 
2×12-y=-10 
24-y=-10 
-y=-34 
y=34