Nora and Esther collected stamps. Nora gave 25% of her stamps to Esther. As a result, Esther's stamps increased by 70%. If Nora had 231 stamps left, find the total number of stamps the two girls had at first.
| |
Nora |
Esther |
Comparing the change
in Esther's stamps |
| Before |
4x7 =
28 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
3x7 =
21 u |
|
17x1 =
17 u |
25% =
25100 =
14 70% =
70100 =
710 The number of stamps that Nora gave to Esther is repeated. Make the number of stamps that Nora gave to Esther the same. LCM of 1 and 7 is 7.
Number of stamps that Nora had in the end = 21 u
21 u = 231
1 u = 231 ÷ 21 = 11
Number of stamps that Nora and Esther had at first
= 28 u + 10 u
= 38 u
= 38 x 11
= 418
Answer(s): 418
