Adam has 74 stickers.
After
310 of the blue stickers is given away and
another 45 red stickers are bought,
there is an equal number of blue and red stickers.
- How many blue stickers are there in the end?
- How many less red stickers than blue stickers are there at first?
- How many blue stickers are given away?
|
Blue |
Red |
Before |
10 u |
7 u - 45 |
Change |
- 3 u |
+ 45 |
After |
7 u |
7 u |
(a)
Fraction of the blue stickers left
= 1 -
310 =
710 The number of blue stickers and red stickers in the end is the same.
Total number of stickers at first
= 10 u + 7 u - 45
= 17 u - 45
17 u - 45 = 74
17 u = 74 + 45
17 u = 119
1 u = 119 ÷ 17 = 7
Number of blue stickers in the end
= 7 u
= 7 x 7
= 49
(b)
Number of less red stickers than blue stickers at first
= 10 u - (7 u - 45)
= 10 u - 7 u + 45
= 3 u + 45
= 3 x 7 + 45
= 21 + 45
= 66
(c)
Number of blue stickers given away
= 3 u
= 3 x 7
= 21
Answer(s): (a) 49; (b) 66; (c) 21