Question 135877
Let L be Luis' age now, b=brother's age.
L=b+10
L+1=3(b+1)
.
b+10+1=3b+3 Substitute b+10 for L.
b+11=3b+3
b-b+11-3=3b-b+3-3
8=2b
2b/2=8/2
b=4
Luis is 14 yo
Next year his brother will be 5.
.
Ed