125. Dear club. Ten people decided to found a club. If there were 5 more people, each would contribute 100 dollars less. How much money did each member contribute?
125. If the original number of participants increases by $50 \%$, then each person's share is only $\frac{2}{3}$ of the previous individual contribution. Thus, 100 dollars constitute $\frac{1}{3}$ of the original contribution, and each club member paid 300 dollars.

$[$ [ M. M., 32, 229 (March 1959).]