The ratio of the number of blue stickers to red stickers is 8 : 5.
After Adam buys another 30 blue stickers and 90 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 7 : 5.
How many stickers does Adam have now?
|
Make p the same (1) x 5 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
40 u |
8 u |
5 u |
35 u |
Change |
+ 150 |
+ 30 |
+ 90 |
+ 630 |
After |
40 u + 150 |
8 u + 30 |
5 u + 90 |
35 u + 630 |
Comparing the blue stickers and the red stickers in the end |
35 p |
7 p |
5 p |
35 p |
8 u + 30 = 7 p --- (1)
5 u + 90 = 5 p --- (2)
Make p the same by using the LCM of 5 and 7.
LCM of 5 and 7 is 35.
(1)
x 5 40 u + 150 = 35 p --- (3)
(2)
x 7 35 u + 630 = 35 p --- (4)
(3) = (4)
40 u + 150 = 35 u + 630
40 u - 35 u = 630 - 150
5 u = 480
1 u = 480 ÷ 5 = 96
Number of stickers that Adam has now
= 8 u + 30 + 5 u + 90
= 8 u + 5 u + 30 + 90
= 13 u + 120
= 13 x 96 + 120
= 1248 + 120
= 1368
Answer(s): 1368