Adam has 172 stickers.
After
37 of the red stickers is given away and
another 15 blue stickers are bought,
there is an equal number of red and blue stickers.
- How many red stickers are there in the end?
- How many less blue stickers than red stickers are there at first?
- How many red stickers are given away?
|
Red |
Blue |
Before |
7 u |
4 u - 15 |
Change |
- 3 u |
+ 15 |
After |
4 u |
4 u |
(a)
Fraction of the red stickers left
= 1 -
37 =
47 The number of red stickers and blue stickers in the end is the same.
Total number of stickers at first
= 7 u + 4 u - 15
= 11 u - 15
11 u - 15 = 172
11 u = 172 + 15
11 u = 187
1 u = 187 ÷ 11 = 17
Number of red stickers in the end
= 4 u
= 4 x 17
= 68
(b)
Number of less blue stickers than red stickers at first
= 7 u - (4 u - 15)
= 7 u - 4 u + 15
= 3 u + 15
= 3 x 17 + 15
= 51 + 15
= 66
(c)
Number of red stickers given away
= 3 u
= 3 x 17
= 51
Answer(s): (a) 68; (b) 66; (c) 51