Adam has 187 stickers.
After
79 of the blue stickers is given away and
another 33 red stickers are bought,
there is an equal number of blue and red stickers.
- How many blue stickers are there in the end?
- How many less red stickers than blue stickers are there at first?
- How many blue stickers are given away?
|
Blue |
Red |
Before |
9 u |
2 u - 33 |
Change |
- 7 u |
+ 33 |
After |
2 u |
2 u |
(a)
Fraction of the blue stickers left
= 1 -
79 =
29 The number of blue stickers and red stickers in the end is the same.
Total number of stickers at first
= 9 u + 2 u - 33
= 11 u - 33
11 u - 33 = 187
11 u = 187 + 33
11 u = 220
1 u = 220 ÷ 11 = 20
Number of blue stickers in the end
= 2 u
= 2 x 20
= 40
(b)
Number of less red stickers than blue stickers at first
= 9 u - (2 u - 33)
= 9 u - 2 u + 33
= 7 u + 33
= 7 x 20 + 33
= 140 + 33
= 173
(c)
Number of blue stickers given away
= 7 u
= 7 x 20
= 140
Answer(s): (a) 40; (b) 173; (c) 140