Two pairs of different sizes contain 34.5 liters of water altogether. when 0.68 liter of water is poured from the bigger pail into the smaller pail, the amount

Let
a = bigger pail
b = smaller pail

So from above, we get :
a + b = 34.5...(1)
a-0.68=9(b+0.68)...(2)

By eliminating the two equations, we simply get :
b + 0.68 = 34.5 - 9b - 6.12
<=>10b = 34.5 - 6.12 - 0.68
<=>10b = 27.7
<=> b = 2.77 liters

Hence, we get a = 34.5 - 2.77 = 31.73 liters.

Thus, the answer is 31.73 liters in the bigger one and 2.77 liters in the smaller one.