Two, four, thirty

3,25

4,4.9*6.4+ 14*0.36-6.4*3.5=(4.9*6.4-6.4*3.5)+ 14*0.36= 1.4*6.4+ 14*0.36

= 1.4*6.4+ 1.4*3.6= 14

5, 1-( 1/ 15+ 1/24)*5/( 1/24)= 1 1

6, two baskets of apples, the second basket is one quarter less than the first basket, and the ratio is 8: 6.

In this way, 4.2 is equivalent to the first basket being reduced by one eighth and the second basket by one sixth, so the first basket is 4.2/( 1/8)=33.6kg, and the second basket is 4.2/( 1/6)=25.2, which is 8.4 more.

7. Calculate the perimeter first. Let the speed of B be V, (6-v)*200=(6+v)*40, and get v=4, so the perimeter is 400.

Straight warp = circumference/pi =400/3

8. The radius of the bottom surface is x, if it is square, then PI*x=4, and the volume is pi * x 2 * 4 =16x =16 * 4/pi = 64/pi.

9. Take 60 yuan.

The part within 60 cubic meters is calculated by 0.8 yuan per cubic meter, and the money of 60 square meters is 48 yuan, which is 12 yuan.

Every cubic meter 1.2 yuan, that is 10 cubic meter, so * * * has 70 square meters.

How much is 60 cubic meters of gas? The part within 60 cubic meters is calculated by 0.8 yuan per cubic meter, and the money of 60 square meters is 48 yuan.

How many cubic meters of gas does Jingjing use? It is still short of 12 yuan, per cubic meter 1.2 yuan, 10 cubic meter, so * * * has 60+ 10 = 70 square meters.