Ryan has 90% as many stamps as Michael. If Ryan gives away 20% of the stamps and Michael gives away 70% of his stamps, they will have 408 stamps altogether. How many stamps do the two of them have?
|
Ryan |
Michael |
Total |
Comparing Ryan and Michael at first |
9x5 = 45 u |
10x5 = 50 u |
|
Before |
5x9 = 45 u |
10x5 = 50 u |
|
Change |
- 1x9 = - 9 u |
- 7x5 = - 35 u |
|
After |
4x9 = 36 u |
3x5 = 15 u |
408 |
90% =
90100 =
910 20% =
20100 =
15 70% =
70100 =
710 The number of stamps that Ryan has at first is repeated. Make the number of stamps that Ryan has the same. LCM of 9 and 5 is 45 u.
The number of stamps that Michael has at first is repeated. Make the number of stamps that Michael has the same. LCM of 10 and 10 is 50 u.
Number of stamps in the end
= 36 u + 15 u
= 51 u
51 u = 408
1 u = 408 ÷ 51 = 8
Total number of stamps that the two of them have
= 45 u + 50 u
= 95 u
= 95 x 8
= 760
Answer(s): 760