There are two pools A and B, which store 40 tons of water. If Pool A injects 4 tons of water and Pool B releases 8 tons of water, then the water storage capacity of Pool A and Pool B is equal. How many tons were originally stored in these two pools? Hurry up! ! ! ! SOS online, etc. There's another one:

Suppose a has x, then b has 40-x tons.

When 4 tons of water is injected into pool A, 8 tons of water is discharged from pool B..

The water storage capacity of the two pools is equal.

therefore

x+4=40-x-8

Get x= 14.

40- 14=26

So the original two pools stored 14 and 26 tons of water respectively.

*** 1 15 members of a school actively participated in fund-raising activities. Some members each donated 10 yuan, and the rest did not give to 4 yuan. If the total donation amount is 790 yuan, how many members donated 10 yuan?

Member X donated money 10 yuan, and member (1 15-X) donated money to 4 yuan.

10X+4×( 1 15-X)= 790

X=55