Adam has 51 stickers.
After
49 of the red stickers is given away and
another 5 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 |
9 u |
5 u - 5 |
Change |
- 4 u |
+ 5 |
After |
5 u |
5 u |
(a)
Fraction of the red stickers left
= 1 -
49 =
59 The number of red stickers and blue stickers in the end is the same.
Total number of stickers at first
= 9 u + 5 u - 5
= 14 u - 5
14 u - 5 = 51
14 u = 51 + 5
14 u = 56
1 u = 56 ÷ 14 = 4
Number of red stickers in the end
= 5 u
= 5 x 4
= 20
(b)
Number of less blue stickers than red stickers at first
= 9 u - (5 u - 5)
= 9 u - 5 u + 5
= 4 u + 5
= 4 x 4 + 5
= 16 + 5
= 21
(c)
Number of red stickers given away
= 4 u
= 4 x 4
= 16
Answer(s): (a) 20; (b) 21; (c) 16