13 students share some stickers.
Each girl gets 3 stickers.
Each boy gets 5 stickers.
In total, the girls get 33 less stickers than the boys.

1. How many girls are there?
2. How many boys are there?
3. How many stickers do the boys get?
4. How many stickers do the students get?

Number of  boys	Total stickers that the boys get	Number of girls	Total stickers that the girls get	Less stickers for the girls than the boys
13	13 x 5 =  65	0	0 x 3 = 0	65 - 0 = 65
12	12 x 5 = 60	1	1 x 3 = 3	60 - 3 = 57
9	9 x 5 = 45	4	4 x 3 = 12	45 - 12 =  33

(a)
Total number of stickers that the students will get if all the students are boys
= 13 x 5
= 65

Total number of less stickers for the girls than the boys if one boy is replaced by a girl
= 12 x 5 - 1 x 3
= 60 - 3
= 57

Big difference in the decrease in the number of stickers when a boy is replaced by a girl
= 65 - 33
= 32

Small difference in the decrease in the number of stickers when a boy is replaced by a girl
= 3 + 5
= 8

Number of girls
= 32 ÷ 8
= 4

(b)
Number of boys
= 13 - 4
= 9

(c)
Number of stickers that the boys get
= 9 x 5
= 45

(d)
Number of stickers that the girls get
= 4 x 3
= 12

Total number of stickers
= 45 + 12
= 57

Answer(s): (a) 4; (b) 9; (c) 45; (d) 57