Adam has 72 red beads.
He has 4 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 3 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 |
4 x 2 = 8 u |
1 x 2 = 2 u |
3 x 2 = 6 u |
Change |
+ ? |
+ ? |
|
After |
3 x 3 = 9 u |
1 x 3 = 3 u |
2 x 3 = 6 u |
(a)
The difference in the number between the red and blue beads at first and in the end remains unchanged.
LCM of 3 and 2 is 6.
8 u = 72
1 u = 72 ÷ 8 = 9
Number of red beads in the end
= 9 u
= 9 x 9
= 81
(b)
Number of blue beads in the end
= 3 u
= 3 x 9
= 27
(c)
Total number of beads in the end
= 81 + 27
= 108
(d)
Total number of beads that Adam buys
= (9 u - 8 u) x 2
= 1 u x 2
= 2 u
= 2 x 9
= 18
Answer(s): (a) 81; (b) 27; (c) 108; (d) 18