2. 192

3.7

4.a

5.b

6.b

7.b

8. Solution: Let the purchase price be X yuan.

( 1+20%)x = 900 *(9/ 10)-48

1.2x=8 10-48

1.2x=762

x=640

9.560×80%=448

400÷448=25/28

1000×60%=600

500÷600=5/6

5/6 < 25/28 B has a high profit.

10.240÷ 1.2=200

240÷0.8=300

240×2=480

240+300=500

500 > 480 lost