Adam has 20 blue marbles and 190 green marbles.
After buying the same number of marbles,
the ratio of the blue marbles and the green marbles becomes 3 : 5.
How many marbles does he buy?
|
Blue |
Green |
Difference |
Before |
20 |
190 |
170 |
Change |
+ ? |
+ ? |
|
After |
3 u |
5 u |
2 u |
At first
Difference in the number of marbles
= 190 - 20
= 170
In the end
Number of blue marbles = 3 u
Number of green marbles = 5 u
Difference in the number of marbles in units
= 5 u - 3 u
= 2 u
The difference in the number of marbles between the blue marbles and the green marbles remains unchanged.
2 u = 170
1 u = 170 ÷ 2 = 85
Number of blue marbles that Adam buys
= 3 u - 20
= 3 x 85 - 20
= 255 - 20
= 235
Total number of marbles that Adam buys
= 2 x 235
= 470
Answer(s): 470