Question 540688
Let x= the youngest sisters age now
x+5  = the middle sisters age now
x+10 = the oldest sisters age now

(x-6)+(x-1)+(x+4)=72
3x-3             =72
-3+3x+3          =72+3
0+3x             =75
3x               =75
1/3×3x           =75×1/3
x                =25


25, 30,35 

CHECK
6 years ago 
19,24,29 
add up
72