Mary and Lynn collected beads. Mary gave 10% of her beads to Lynn. As a result, Lynn's beads increased by 70%. If Mary had 630 beads left, find the total number of beads the two girls had at first.
| |
Mary |
Lynn |
Comparing the change
in Lynn's beads |
| Before |
10x7 =
70 u |
|
10x1 =
10 u |
| Change |
- 1x7 =
- 7 u |
+ 1x7 =
+ 7 u |
+ 7x1 =
+ 7 u |
| After |
9x7 =
63 u |
|
17x1 =
17 u |
10% =
10100 =
110 70% =
70100 =
710 The number of beads that Mary gave to Lynn is repeated. Make the number of beads that Mary gave to Lynn the same. LCM of 1 and 7 is 7.
Number of beads that Mary had in the end = 63 u
63 u = 630
1 u = 630 ÷ 63 = 10
Number of beads that Mary and Lynn had at first
= 70 u + 10 u
= 80 u
= 80 x 10
= 800
Answer(s): 800
