1. solution: suppose class one gets x balls, then class two gets (120-x) balls.

1/3x = 1/2( 120-x)

1/3x=60- 1/2x

1/3x+ 1/2x=60

5/6x=60

x=72

120-x= 120-72=48 (pieces)

A: Class One is assigned to 72, and Class Two is assigned to 48.

2. Solution: Suppose A has x tons, then B has (420-x) tons.

25% x+ 1/3(420-x)= 125

25% x+ 140- 1/3x = 125

- 1/ 12x = 125- 140

- 1/ 12x=- 15

x= 180

420- 180=240 (ton)

A: A 180 tons, B 240 tons.