Gabby and Lucy collected cards. Gabby gave 20% of her cards to Lucy. As a result, Lucy's cards increased by 70%. If Gabby had 336 cards left, find the total number of cards the two girls had at first.
| |
Gabby |
Lucy |
Comparing the change
in Lucy's cards |
| Before |
5x7 =
35 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
4x7 =
28 u |
|
17x1 =
17 u |
20% =
20100 =
15 70% =
70100 =
710 The number of cards that Gabby gave to Lucy is repeated. Make the number of cards that Gabby gave to Lucy the same. LCM of 1 and 7 is 7.
Number of cards that Gabby had in the end = 28 u
28 u = 336
1 u = 336 ÷ 28 = 12
Number of cards that Gabby and Lucy had at first
= 35 u + 10 u
= 45 u
= 45 x 12
= 540
Answer(s): 540
