Crate J contains 18 red beads and 8 black beads. Crate K contains 17 red beads and 17 black beads. How many black beads and red beads must be moved from Crate K to put into Crate J so that 50% of the beads in Crate A are red and 75% of the beads in Crate K are red?
|
Crate J |
Crate K |
|
Red beads |
Black beads |
Red beads |
Black beads |
Before |
18 |
8 |
17 |
17 |
Change |
+ ? |
+ ? |
- ? |
- ? |
After |
1 u |
1 u |
3 p |
1 p |
50% =
50100 = 12
75% =
75100 = 34
Number of red beads = 18 + 17 = 35
Number of black beads = 8 + 17 = 25
1 u + 3 p = 35 --- (1)
1 u + 1 p = 25 ---(2)
(1) - (2)
(1 u + 3 p) - (1 u + 1 p) = 35 - 25
3 p - 1 p = 10
2 p = 10
1 p = 10 ÷ 2 = 5
From (2):
1 u + 1 p = 25
1 u + 1 x 5 = 25
1 u + 5 = 25
1 u = 25 - 5 = 20
Number of black beads to be moved from Crate K to Crate J
= 17 - 1 p
= 17 - 1 x 5
= 17 - 5
= 12
Number of red beads to be moved from Crate K to Crate J
= 1 u - 18
= 20 - 18
= 2
Total number of black and red beads to be moved from Crate K to Crate J
= 12 + 2
= 14
Answer(s): 14