The ratio of the number of red stickers to blue stickers is 7 : 3.
After Adam gives away 16 red stickers and gives away 18 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 9 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 9 = (4) |
Before |
14 u |
7 u |
3 u |
27 u |
Change |
- 32 |
- 16 |
- 18 |
- 162 |
After |
18 p |
9 p |
2 p |
18 p |
7 u - 16 = 9 p --- (1)
3 u - 18 = 2 p --- (2)
Make p the same.
(1) x 2
14 u - 32 = 18 p --- (3)
(2) x 9
27 u - 162 = 18 p --- (4)
(4) = (3)
27 u - 162 = 14 u - 32
27 u - 14 u = 162 - 32
13 u = 130
1 u = 130 ÷ 13 = 10
Number of stickers that Adam has now
= 7 u - 16 + 3 u - 18
= 10 u - 34
= 10 x 10 - 34
= 100 - 34
= 66
Answer(s): 66