The average number of stickers that Bryan and Adam have is 26.
The average number of stickers that Bryan and Charlie have is 56.
The number of stickers that Adam has is ²₇ as many as Charlie.

1. How many stickers does Bryan have?
2. How many stickers does Adam have?
3. How many stickers does Charlie have?

(a)
Number of stickers that Bryan and Adam has
= 2 x 26
= 52

Number of stickers that Bryan and Charlie has
= 2 x 56
= 112

Number of stickers that Adam has = 2 u
Number of stickers that Charlie has = 7 u

Let the number of Bryan's stickers be B.
Let the number of Adam's stickers be A.
Let the number of Charlie's stickers be C.


B + A = 52
B + 2 u = 52 --- (1)

B + C = 112
B + 7 u = 112 --- (2)

(2) - (1)
(B + 7 u) - (B + 2 u ) = 112 - 52
B + 7 u - B - 2 u = 60
B - B + 7 u - 2 u = 60

5 u = 60

1 u = 60 ÷ 5 = 12

Substitute 1 u = 12 into (1).
B + 2 x 12 = 52
B + 24 = 52
B = 52 - 24 = 28

Number of stickers that Bryan has = 28

(b)
Number of stickers that Adam has
= 2 u
= 2 x 12
= 24

(c)
Number of stickers that Charlie has
= 7 u
= 7 x 12
= 84

Answer(s): (a) 28; (b) 24; (c) 84