Adam has 90 red beads.
He has 6 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 |
6 x 1 = 6 u |
1 x 1 = 1 u |
5 x 1 = 5 u |
Change |
+ ? |
+ ? |
|
After |
2 x 5 = 10 u |
1 x 5 = 5 u |
1 x 5 = 5 u |
(a)
The difference in the number between the red and blue beads at first and in the end remains unchanged.
LCM of 5 and 1 is 5.
6 u = 90
1 u = 90 ÷ 6 = 15
Number of red beads in the end
= 10 u
= 10 x 15
= 150
(b)
Number of blue beads in the end
= 5 u
= 5 x 15
= 75
(c)
Total number of beads in the end
= 150 + 75
= 225
(d)
Total number of beads that Adam buys
= (10 u - 6 u) x 2
= 4 u x 2
= 8 u
= 8 x 15
= 120
Answer(s): (a) 150; (b) 75; (c) 225; (d) 120