Please help first answer will get marked brainiest!

Mari=16, Carlos=21, Amanda=63

Mari: M
Carlos: M + 5
Amanda: 3(M + 5)
Total: 100
Mari + Carlos + Amanda = Total
M + M + 5 + 3(M + 5) = 100
2M + 5 + 3M + 15 = 100
5M + 20 = 100
5M = 80
M = 16
Carlos (C): M + 5 = (16) + 5 = 21
Amanda (A): 3(M + 5) = 3(16 + 5) = 3(21) = 63
Mari=16, Carlos=21, Amanda=63

hope this helps!