Adam has 75 red beads.
He has 5 times as many red beads as blue beads.
After he buys an equal number of red and blue beads,
the number of red beads is 2 times that of the blue beads.
- How many red beads are there in the end?
- How many blue beads are there in the end?
- How many beads are there in the end?
- How many beads does Adam buy?
|
Red beads |
Blue beads |
Difference |
Before |
5 x 1 = 5 u |
1 x 1 = 1 u |
4 x 1 = 4 u |
Change |
+ ? |
+ ? |
|
After |
2 x 4 = 8 u |
1 x 4 = 4 u |
1 x 4 = 4 u |
(a)
The difference in the number between the red and blue beads at first and in the end remains unchanged.
LCM of 4 and 1 is 4.
5 u = 75
1 u = 75 ÷ 5 = 15
Number of red beads in the end
= 8 u
= 8 x 15
= 120
(b)
Number of blue beads in the end
= 4 u
= 4 x 15
= 60
(c)
Total number of beads in the end
= 120 + 60
= 180
(d)
Total number of beads that Adam buys
= (8 u - 5 u) x 2
= 3 u x 2
= 6 u
= 6 x 15
= 90
Answer(s): (a) 120; (b) 60; (c) 180; (d) 90