Adam has red and blue stickers in the ratio of 1 : 7.
When 70 blue stickers are replaced with the same number of red stickers,
the ratio of the number of red and blue stickers will be 5 : 7
How many stickers are there altogether?
|
Red |
Blue |
Total |
Before |
1 x 3 = 3 u |
7 x 3 = 21 u |
8 x 3 = 24 u |
Change |
+ 70 |
- 70 |
|
After |
5 x 2 = 10 u |
7 x 2 = 14 u |
12 x 2 = 24 u |
When 70 blue stickers are replaced with the same number of red stickers, the total number of stickers remains unchanged.
Make the total number of stickers the same using the LCM of 8 and 12.
LCM of 8 and 12 = 24
Number of blue stickers that is replaced by red stickers
= 10 u - 3 u
= 7 u
7 u = 70
1 u = 70 ÷ 7 = 10
Total number of stickers
= 24 u
= 24 x 10
= 240
Answer(s): 240