Solution: Suppose my son is X years old and my father is 3x years old this year.

3×5 = 4(x-5)

3x-5=4x-20

4x-3x=20-5

x= 15

3x=3* 15=45

A: My father is 45 years old and my son 15 years old.

2.

1) solution: let the total number of passengers be X.

x( 1-4/7- 1/3)=42

x*2/2 1=42

x=42*2 1/2

X=44 1 person

2)

More men than women:

441* (4/7-1/3) = 441* 5/21=105 people.

3.

Solution: Let the date in the upper left corner be X and the date in the upper right corner be x+ 1.

X+7 is in the lower left corner and x+8 is in the lower right corner.

x+x+ 1+x+7+x+8=44

4x+ 16=44

4x=28

x=7

x+ 1=7+ 1=8

x+7=7+7= 14

x+8=7+8= 15

A: The dates in the box are 7, 8, 14 and 15.

4.

Is it 15x+45x= 180?

Title:

The distance between Party A and Party B is 180km, and Xiao Wang travels from Party A to Party B every hour15km; Xiaoli travels from B to A at a speed of 45 kilometers per hour. How many hours did they meet?

15x+45x= 180

60x= 180

x=3

Meet me in three hours.