Question 959256
M=Manuel's age; S=sister's age=M-8yrs
M-3yrs=3(S-3yrs) Substitute for S
M-3yrs=3(M-8yrs-3yrs)
M-3yrs=3M-33yrs Add 33yrs to each side.
M+30 yrs=3M Subtract M from each side.
30 yrs=2M Divide each side by 2.
15 yrs=M ANSWER 1: Manuel is 15 years old
S=M-8yrs=15yrs-8yrs=7yrs ANSWER 2: Sister is 7 years old
CHECK:
M-3yrs=3(S-3yrs)
15yrs-3yrs=3(7yrs-3yrs)
12yrs=3(4yrs)
12yrs=12yrs