PSLE Rachel had a box of gold beads and blue beads in the ratio 17 : 7. She removed an equal number of gold beads and blue beads from the box. The ratio of the number of gold beads and blue beads left in the box became 7 : 2. What percentage of the beads were left in the box?
|
Gold beads |
Blue beads |
Difference |
Total |
Before |
17x1 = 17 u |
7x1 = 7 u |
10x1 = 10 u |
24x1 = 24 u |
Change |
- 3 u |
- 3 u |
|
|
After |
7x2 = 14 u |
2x2 = 4 u |
5x2 = 10 u |
9x2 = 18 u |
When Rachel removed an equal number of gold beads and blue beads, the difference between the number of gold beads and blue beads at first and in the end remains the same.
LCM of 10 and 5 is 10.
Percentage of the beads left in the box
=
1824 x 100%
= 34 x 100%
= 75%
Answer: 75%