PSLE Usha had an equal number of grey and red beads. She gave 20 grey beads and 16 red beads to Mary. She gave the remaining beads to Nora. Nora was given 5 grey beads for every 7 red beads. How many beads did Usha have at first?
|
Grey |
Red |
Before |
5 u + 20 |
7 u + 16 |
Change |
- 20 |
- 16 |
After |
5 u |
7 u |
The number of grey and red beads is equal at first.
5 u + 20 = 7 u + 16
7 u - 5 u = 20 - 16
2 u = 4
1 u = 4 ÷ 2 = 2
Number of grey beads that Usha had at first
= 5 u + 20
= 5 x 2 + 20
= 10 + 20
= 30
Number of beads that Usha had at first
= 2 x 30
= 60
Answer(s): 60