Winnie and Zara collected stamps. Zara gave 70% of her stamps to Winnie. As a result, Winnie's stamps increased by 10%. If Winnie had 385 stamps left, find the total number of stamps the two girls had at first.
| |
Comparing the change
in Zara's stamps |
Zara |
Winnie |
| Before |
10x1 =
10 u |
|
10x7 =
70 u |
| Change |
- 7x1 =
- 7 u |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
| After |
3x1 =
3 u |
|
11x7 =
77 u |
70% =
70100 =
710 10% =
10100 =
110 The number of stamps that Winnie gave to Zara is repeated. Make the number of stamps that Winnie gave to Zara the same. LCM of 1 and 7 is 7.
Number of stamps that Winnie had in the end = 77 u
77 u = 385
1 u = 385 ÷ 77 = 5
Number of stamps that Zara and Winnie had at first
= 10 u + 70 u
= 80 u
= 80 x 5
= 400
Answer(s): 400
