Adam has 36 red marbles.
He has 6 times as many red marbles as blue marbles.
After he buys an equal number of red and blue marbles,
the number of red marbles is 3 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 buy?
|
Red marbles |
Blue marbles |
Difference |
Before |
6 x 2 = 12 u |
1 x 2 = 2 u |
5 x 2 = 10 u |
Change |
+ ? |
+ ? |
|
After |
3 x 5 = 15 u |
1 x 5 = 5 u |
2 x 5 = 10 u |
(a)
The difference in the number between the red and blue marbles at first and in the end remains unchanged.
LCM of 5 and 2 is 10.
12 u = 36
1 u = 36 ÷ 12 = 3
Number of red marbles in the end
= 15 u
= 15 x 3
= 45
(b)
Number of blue marbles in the end
= 5 u
= 5 x 3
= 15
(c)
Total number of marbles in the end
= 45 + 15
= 60
(d)
Total number of marbles that Adam buys
= (15 u - 12 u) x 2
= 3 u x 2
= 6 u
= 6 x 3
= 18
Answer(s): (a) 45; (b) 15; (c) 60; (d) 18