Adam has 118 stickers.
After
29 of the red stickers is given away and
another 42 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 |
7 u - 42 |
Change |
- 2 u |
+ 42 |
After |
7 u |
7 u |
(a)
Fraction of the red stickers left
= 1 -
29 =
79 The number of red stickers and blue stickers in the end is the same.
Total number of stickers at first
= 9 u + 7 u - 42
= 16 u - 42
16 u - 42 = 118
16 u = 118 + 42
16 u = 160
1 u = 160 ÷ 16 = 10
Number of red stickers in the end
= 7 u
= 7 x 10
= 70
(b)
Number of less blue stickers than red stickers at first
= 9 u - (7 u - 42)
= 9 u - 7 u + 42
= 2 u + 42
= 2 x 10 + 42
= 20 + 42
= 62
(c)
Number of red stickers given away
= 2 u
= 2 x 10
= 20
Answer(s): (a) 70; (b) 62; (c) 20