Adam has 111 stickers.
After
58 of the red stickers is given away and
another 21 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 |
8 u |
3 u - 21 |
Change |
- 5 u |
+ 21 |
After |
3 u |
3 u |
(a)
Fraction of the red stickers left
= 1 -
58 =
38 The number of red stickers and blue stickers in the end is the same.
Total number of stickers at first
= 8 u + 3 u - 21
= 11 u - 21
11 u - 21 = 111
11 u = 111 + 21
11 u = 132
1 u = 132 ÷ 11 = 12
Number of red stickers in the end
= 3 u
= 3 x 12
= 36
(b)
Number of less blue stickers than red stickers at first
= 8 u - (3 u - 21)
= 8 u - 3 u + 21
= 5 u + 21
= 5 x 12 + 21
= 60 + 21
= 81
(c)
Number of red stickers given away
= 5 u
= 5 x 12
= 60
Answer(s): (a) 36; (b) 81; (c) 60