Rabbits have two legs.

48=X+2X

48 = 3 times

X=48/3

X= 16

9. Let the sum of one book in each of the two series be (2.5+3)X yuan.

22=(2.5+3)X

22 = 5.5 times

X=22/5.5

X=4

1 1. Let the number be x.

18=(24- 15)X

18=9X

X= 18/9

X=2

12

X+ 100=3X

100=3X-X

X= 100/2

X=50

think

three