Adam has 24 blue marbles.
He has 4 times as many blue marbles as red marbles.
After he buys an equal number of blue and red marbles,
the number of blue marbles is 2 times that of the red marbles.
- How many blue marbles are there in the end?
- How many red marbles are there in the end?
- How many marbles are there in the end?
- How many marbles does Adam buy?
|
Blue marbles |
Red marbles |
Difference |
Before |
4 x 1 = 4 u |
1 x 1 = 1 u |
3 x 1 = 3 u |
Change |
+ ? |
+ ? |
|
After |
2 x 3 = 6 u |
1 x 3 = 3 u |
1 x 3 = 3 u |
(a)
The difference in the number between the blue and red marbles at first and in the end remains unchanged.
LCM of 3 and 1 is 3.
4 u = 24
1 u = 24 ÷ 4 = 6
Number of blue marbles in the end
= 6 u
= 6 x 6
= 36
(b)
Number of red marbles in the end
= 3 u
= 3 x 6
= 18
(c)
Total number of marbles in the end
= 36 + 18
= 54
(d)
Total number of marbles that Adam buys
= (6 u - 4 u) x 2
= 2 u x 2
= 4 u
= 4 x 6
= 24
Answer(s): (a) 36; (b) 18; (c) 54; (d) 24