Adam has 35 red marbles.
He has 5 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 |
5 x 1 = 5 u |
1 x 1 = 1 u |
4 x 1 = 4 u |
Change |
+ ? |
+ ? |
|
After |
3 x 2 = 6 u |
1 x 2 = 2 u |
2 x 2 = 4 u |
(a)
The difference in the number between the red and blue marbles at first and in the end remains unchanged.
LCM of 4 and 2 is 4.
5 u = 35
1 u = 35 ÷ 5 = 7
Number of red marbles in the end
= 6 u
= 6 x 7
= 42
(b)
Number of blue marbles in the end
= 2 u
= 2 x 7
= 14
(c)
Total number of marbles in the end
= 42 + 14
= 56
(d)
Total number of marbles that Adam buys
= (6 u - 5 u) x 2
= 1 u x 2
= 2 u
= 2 x 7
= 14
Answer(s): (a) 42; (b) 14; (c) 56; (d) 14