Xandra had some brown beads and gold beads in 2 boxes. In Box A, the ratio of the number of brown beads to gold beads was 9 : 5. In Box B, the number of brown beads was 4 times the number of gold beads. Xandra transferred
35 of the gold beads from Box A to Box B. The number of beads in Box A became 77 and the ratio of the number of brown beads to gold beads in Box B became 8 : 9.
- How many gold beads were transferred from Box A to Box B?
- What was the number of beads in Box B after the transfer?
|
Box A |
Box B |
|
Brown |
Gold |
Brown |
Gold |
Comparing brown beads and gold beads at first |
9 u |
5 u |
4x2 = 8 p |
1x2 = 2 p |
Before |
|
5 u |
|
|
Change |
|
- 3 u |
|
+ 3 u |
After |
|
2 u |
|
|
Comparing brown beads and gold beads in the end |
9 u |
2 u |
8 p |
9 p |
(a)
Total number of beads in the end for Box A
= 9 u + 2 u
= 11 u
11 u = 77
1 u = 77 ÷ 11 = 7
Number of gold beads that were transferred from Box A to Box B
= 3 u
= 3 x 7
= 21
(b)
The number of brown beads in Box B remains unchanged. Make the number of brown beads in Box B the same. LCM of 4 and 8 is 8.
Increase in the number of gold beads in Box B
= 9 p - 2 p
= 7 p
7 p = 3 u
7 p = 21
1 p = 21 ÷ 7 = 3
Number of beads in Box B in the end
= 8 p + 9 p
= 17 p
= 17 x 3
= 51
Answer(s): (a) 21; (b) 51