600/X+(4800-600)/2x=9

5400/2x=9

x=300

2. Let the speed of the first team be x km/h..

90/X=90/ 1.5X+0.5

45/ 1.5X=0.5

X=60

The speed of the second team is 1.5X, which is 90km/h.

3. a set of nectarines is x yuan a catty

80/X-5=80/2X

40/X=5

X=8

The price of cherries is 2X, that is, 16 yuan a catty.