Maths Homework?

Question

Xavier, Yati and Zachary shared some marbles. Xavier had 1/3 of what Yati and Zachary had. Yati had 1/5 of what Xavier and Zachary had. Xavier had 24 fewer marbles than Zachary. How many marbles do they have altogether? Answer is 72 but I do not know the steps. Can someone help, pls do not use algebra. thks!

Answer 1

x = 1/3(y + z) so 3x = y + z
y = 1/5(x + z) so 5y = x + z
x = z -24
insert above
3(z -24) = 3z - 72 = y + z
2z = y + 72

and
5y = z - 24 + z = 2z - 24
from above
5y = (y + 72) -24 = y + 48
4y = 48
y = 12

2z = 84
z = 42

x = 18

x + y + z = 18 + 12 + 42 = 72