The ratio of the number of blue stickers to red stickers is 7 : 1.
After Adam buys another 35 red stickers and gives away 21 blue stickers,
the ratio becomes of the number of blue stickers to red stickers is 7 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
14 u |
7 u |
1 u |
7 u |
Change |
- 42 |
- 21 |
+ 35 |
+ 245 |
After |
14 p |
7 p |
2 p |
14 p |
7 u + 35 = 7 p --- (1)
1 u - 21 = 2 p --- (2)
Make p the same.
(1)
x 214 u - 42 = 14 p --- (3)
(2)
x 77 u + 245 = 14 p --- (4)
(3) = (4)
14 u - 42 = 7 u + 245
14 u - 7 u = 42 + 245
7 u = 287
1 u = 287 ÷ 7 = 41
Number of stickers that Adam have now
= 7 u + 35 + 1 u - 21
= 7 u + 1 u + 35 - 21
= 8 u + 14
= 8 x 41 + 14
= 328 + 14
= 342
Answer(s): 342