Ryan has 90% as many stamps as Howard. If Ryan gives away 20% of the stamps and Howard gives away 70% of his stamps, they will have 408 stamps altogether. How many stamps do the two of them have?
| |
Ryan |
Howard |
Total |
Comparing Ryan
and Howard 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 Howard has at first is repeated. Make the number of stamps that Howard 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
