Fill in the blanks in units (Eg 3 u) or unit equations (Eg 1 u + 2).

Charlie, Bryan and Adam have some marbles.
After Charlie's number of marbles is doubled,
Bryan's number of marbles is increased by 17 and
Adam's number of marbles is reduced by 11,
the ratio of the number of stickers of Charlie to Bryan to Adam becomes 8 : 9 : 7.

Let the number of stickers that Adam has in the end be 7 u.

1. Number of marbles that Charlie has at first = _____
2. Number of marbles that Bryan has at first = _____
3. Number of marbles that Adam has at first = _____
4. Total number of marbles that they have at first = _____

	Charlie	Bryan	Adam
Before	4 u	9 u - 17	7 u + 11
Change	x 2	+ 17	- 11
After	8 u	9 u	7 u

(a)
Change information into units.

Number of marbles that Charlie has at first
= 8 u ÷ 2
= 4 u

(b)
Number of marbles that Bryan has at first = 9 u - 17

(c)
Number of marbles that Adam has at first = 7 u + 11

(d)
Total number of marbles that they have at first
= 4 u + 9 u - 17 + 7 u + 11
= 4 u + 9 u + 7 u - 17 + 11 
= 20 u - 6

Answer(s): (a) 4 u; (b) 9 u - 17; (c) 7 u + 11; (d) 20 u - 6