Adam has 400 red marbles.
He has 4 times as many red marbles than blue marbles.
After he gives away an equal number of red and blue marbles,
the number of red marbles is 6 times that of the blue marbles.
- How many red marbles are there in the end?
- How many blue marbles are there in the end?
- How many marbles are there in the end?
- How many marbles does Adam give away?
|
Red marbles |
Blue marbles |
Difference |
Before |
4 x 5 = 20 u |
1 x 5 = 5 u |
3 x 5 = 15 u |
Change |
- ? |
- ? |
|
After |
6 x 3 = 18 u |
1 x 3 = 3 u |
5 x 3 = 15 u |
(a)
The difference in the number between the red and blue marbles at first and in the end remains unchanged.
LCM of 3 and 5 is 15.
20 u = 400
1 u = 400 ÷ 20 = 20
Number of red marbles in the end
= 18 u
= 18 x 20
= 360
(b)
Number of blue marbles in the end
= 3 u
= 3 x 20
= 60
(c)
Total number of marbles in the end
= 360 + 60
= 420
(d)
Total number of marbles that Adam gives away
= (20 u - 18 u) x 2
= 2 u x 2
= 4 u
= 4 x 20
= 80
Answer(s): (a) 360; (b) 60; (c) 420; (d) 80