Umur susan 2/5 umur widy, umur susan 3/4 umur merry, selisih umur susan dan widy adalah 18 tahun. Berapa umur mereka masing-masing?

S = 2/5W
S = 3/4M
W-S = 18  -> S = W - 18

W-18 = 2/5W
3/5W = 18
W = 18*5/3 = 30

S = W - 18
S = 30 - 18
S = 12

S = 3/4M
12 = 3/4M
M = 12*4/3
M = 16