Exercise 2

1、X= 12 X= 15 X=2

2 、( 1)3X； 3X+X； 3X -X

(2)2.3X； x+2.3X； 2.3 times–x times

3. Let Xiaohong be X years old and Dad be 4X years old.

Xiaohong: 4X-X=30

X= 10

Dad: 4X=40 A: Dad is 40 years old and Xiaohong 10 years old.

4. Suppose there are X students in grade four, and 1.2X students are in grade five.

X+ 1.2X=264

X= 120

264- 120= 144 (person) A: There are 120 people in the fourth grade and 144 people in the fifth grade.

5. Suppose there are X red-crowned cranes and 2.2X swans.

X+2.2X=960

X=300

960-300=660 (only) A: There are 300 red-crowned cranes and 660 swans.

6、X=3 X= 1. 1 X=5

X=8 X=2 X=4

7. Suppose two people meet after X point.

58X+62X=960

X=8

A: Eight minutes later, the two met.

8. Suppose the distance between the two ships is 182km after x hours.

24.5 times +27.5 times = 182

X=3.5

A: After 3.5 hours, the distance between the two ships is 182km.

9. Let the average CD be X yuan.

8X+ 10X=2 16

X= 12

A: CD average 12 yuan.

10, and each ticket is set at RMB x.

145X- 132X=65

X= 13

A: Each ticket 13 yuan.

1 1, assuming that each person plants X trees on average.

14X- 10X=20

X=5

On average, each person plants 5 trees.

Suppose that after the score of X, A ran 1 lap more than B.

280X-240X=400

X= 10

A: 10 minutes later, A ran more than B 1 lap.