Answer:
21, 15, 7
Step-by-step explanation:
you can write it as a a system of equations
x=older child y= younger child m=middle child
x=3y (oldest age is 3 times the youngest)
m=y+8 (middle is 8 years older than the youngest)
x+y+m=43 (sum of their ages = 43)
rewrite the third in terms of the youngest
3y + y + (y+8) = 43
5y = 35 therefore y=35/7=7
then
m=y+8= 7+8= 15
x=3y=3*7=21
