Adam has 81 stickers.
After
27 of the green stickers is given away and
another 27 red stickers are bought,
there is an equal number of green and red stickers.
- How many green stickers are there in the end?
- How many less red stickers than green stickers are there at first?
- How many green stickers are given away?
|
Green |
Red |
Before |
7 u |
5 u - 27 |
Change |
- 2 u |
+ 27 |
After |
5 u |
5 u |
(a)
Fraction of the green stickers left
= 1 -
27 =
57 The number of green stickers and red stickers in the end is the same.
Total number of stickers at first
= 7 u + 5 u - 27
= 12 u - 27
12 u - 27 = 81
12 u = 81 + 27
12 u = 108
1 u = 108 ÷ 12 = 9
Number of green stickers in the end
= 5 u
= 5 x 9
= 45
(b)
Number of less red stickers than green stickers at first
= 7 u - (5 u - 27)
= 7 u - 5 u + 27
= 2 u + 27
= 2 x 9 + 27
= 18 + 27
= 45
(c)
Number of green stickers given away
= 2 u
= 2 x 9
= 18
Answer(s): (a) 45; (b) 45; (c) 18