Daniel had 4 times as many coins as Harry at first. Then each of them bought an equal number of new coins. In the end, Harry had 21 coins and Daniel had 3 times as many coins as Harry. How many coins did both of them buy altogether?
| |
Daniel |
Harry |
Difference |
| Before |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change |
+ ? |
+ ? |
|
| After |
3x3 =
9 u |
1x3 =
3 u |
2x3 =
6 u |
The difference in the number of coins at first and in the end remains unchanged. Make the difference in the number of coins at first and in the end the same. LCM of 3 and 2 is 6.
Number of coins that Harry had in the end = 3 u
3 u = 21
1 u = 21 ÷ 3 = 7
Number of coins that Daniel bought
= 9 u - 8 u
= 1 u
Number of coins that both of them bought altogether
= 2 x 1 u
= 2 u
= 2 x 7
= 14
Answer(s): 14
