Adam has 191 stickers.
After
79 of the red stickers is given away and
another 7 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 |
2 u - 7 |
Change |
- 7 u |
+ 7 |
After |
2 u |
2 u |
(a)
Fraction of the red stickers left
= 1 -
79 =
29 The number of red stickers and blue stickers in the end is the same.
Total number of stickers at first
= 9 u + 2 u - 7
= 11 u - 7
11 u - 7 = 191
11 u = 191 + 7
11 u = 198
1 u = 198 ÷ 11 = 18
Number of red stickers in the end
= 2 u
= 2 x 18
= 36
(b)
Number of less blue stickers than red stickers at first
= 9 u - (2 u - 7)
= 9 u - 2 u + 7
= 7 u + 7
= 7 x 18 + 7
= 126 + 7
= 133
(c)
Number of red stickers given away
= 7 u
= 7 x 18
= 126
Answer(s): (a) 36; (b) 133; (c) 126