Lucy and Joelle collected cards. Joelle gave 70% of her cards to Lucy. As a result, Lucy's cards increased by 40%. If Lucy had 588 cards left, find the total number of cards the two girls had at first.
| |
Comparing the change
in Joelle's cards |
Joelle |
Lucy |
| Before |
10x2 =
20 u |
|
5x7 =
35 u |
| Change |
- 7x2 =
- 14 u |
- 2x7 =
- 14 u |
+ 2x7 =
+ 14 u |
| After |
3x2 =
6 u |
|
7x7 =
49 u |
70% =
70100 =
710 40% =
40100 =
25 The number of cards that Lucy gave to Joelle is repeated. Make the number of cards that Lucy gave to Joelle the same. LCM of 2 and 7 is 14.
Number of cards that Lucy had in the end = 49 u
49 u = 588
1 u = 588 ÷ 49 = 12
Number of cards that Joelle and Lucy had at first
= 20 u + 35 u
= 55 u
= 55 x 12
= 660
Answer(s): 660
