Adam has 80 blue marbles.
He has 2 times as many blue marbles than red marbles.
After he gives away an equal number of blue and red marbles,
the number of blue marbles is 5 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 give away?
|
Blue marbles |
Red marbles |
Difference |
Before |
2 x 4 = 8 u |
1 x 4 = 4 u |
1 x 4 = 4 u |
Change |
- ? |
- ? |
|
After |
5 x 1 = 5 u |
1 x 1 = 1 u |
4 x 1 = 4 u |
(a)
The difference in the number between the blue and red marbles at first and in the end remains unchanged.
LCM of 1 and 4 is 4.
8 u = 80
1 u = 80 ÷ 8 = 10
Number of blue marbles in the end
= 5 u
= 5 x 10
= 50
(b)
Number of red marbles in the end
= 1 u
= 1 x 10
= 10
(c)
Total number of marbles in the end
= 50 + 10
= 60
(d)
Total number of marbles that Adam gives away
= (8 u - 5 u) x 2
= 3 u x 2
= 6 u
= 6 x 10
= 60
Answer(s): (a) 50; (b) 10; (c) 60; (d) 60