The ratio of the number of blue stickers to red stickers is 7 : 3.
After Adam buys another 46 red stickers and gives away 40 blue stickers,
the ratio becomes of the number of blue stickers to red stickers is 5 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 5 = (4) |
Before |
28 u |
7 u |
3 u |
15 u |
Change |
- 160 |
- 40 |
+ 46 |
+ 230 |
After |
20 p |
5 p |
4 p |
20 p |
7 u + 46 = 5 p --- (1)
3 u - 40 = 4 p --- (2)
Make p the same.
(1)
x 428 u - 160 = 20 p --- (3)
(2)
x 515 u + 230 = 20 p --- (4)
(3) = (4)
28 u - 160 = 15 u + 230
28 u - 15 u = 160 + 230
13 u = 390
1 u = 390 ÷ 13 = 30
Number of stickers that Adam have now
= 7 u + 46 + 3 u - 40
= 7 u + 3 u + 46 - 40
= 10 u + 6
= 10 x 30 + 6
= 300 + 6
= 306
Answer(s): 306