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Four-question mathematics
1. From "the ratio of bookshelf A to bookshelf B is 2: 3", it is concluded that bookshelf A accounts for 2/(3+2)=2/5 of the total.

From "42 books from B to A, the ratio of A to B is 5: 4", 42 books from A account for 5/(5+4)=5/9 of the total.

Then 42 accounts for 5/9-2/5=7/45 of the total.

Total = 42(7/45)= 270 (Ben)

A =270*(2/5)= 108 (Ben)

2. Divide the square into 9 areas, and choose 5 to form a cube.

The side length of a cube is: 27÷3=9 (cm).

The volume of the paper box is 9×9×9=729 (cubic centimeter).

According to the topic, if there are five girls missing, they are boys.

1- 1/ 1 1= 10/ 1 1,

At this time, the total number of people is: 152-5= 147.

Then the boy is:147/[1+10/1] = 77.

There used to be 152-77=75 girls.

4. x male employees and x female employees135-x.

2X/3+4( 135-X)/5=98

10X+ 12( 135-X)= 98 * 15

-2X=- 150

X=75

135-75=60

A: There are 60 male workers and 75 female workers.

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