PSLE Zoe had an equal number of black and brown beads. She gave 36 black beads and 20 brown beads to Mary. She gave the remaining beads to Nora. Nora was given 5 black beads for every 7 brown beads. How many beads did Zoe have at first?
|
Black |
Brown |
Before |
5 u + 36 |
7 u + 20 |
Change |
- 36 |
- 20 |
After |
5 u |
7 u |
The number of black and brown beads is equal at first.
5 u + 36 = 7 u + 20
7 u - 5 u = 36 - 20
2 u = 16
1 u = 16 ÷ 2 = 8
Number of black beads that Zoe had at first
= 5 u + 36
= 5 x 8 + 36
= 40 + 36
= 76
Number of beads that Zoe had at first
= 2 x 76
= 152
Answer(s): 152