Question 360355
g + b = 26 y
 
g-3 = 4(b-3)
 
 
Subtraction of equ. 2 from equ. 1 gives an equation for b only : 
 
 
b + 3 = 26 - 4b + 12 | +4b on both side
 
5b + 3 = 38..........| less 3
 
5b = 35..............| divided by 5
 
b = 7 y : age of brother is seven years, age of girls is 26-7 = 19 y.
 
 
Verification : 
 
sum = 19 + 7 = 26
 
3 years ago : 16 = 4 * 4, 4 = 7-3.