Mary had 12 more coins than Sabrina. After Sabrina gave away
13 of her coins, Mary had thrice as many coins as Sabrina. How many coins did Sabrina have at first?
| |
Mary |
Sabrina |
Comparing Mary and
Sabrina at first |
12 more |
|
| Before |
6 u |
3 u |
| Change |
|
- 1 u |
| After |
6 u |
2 u |
Comparing Mary and
Sabrina in the end |
3x2 =
6 u |
1x2 =
2 u |
Number of coins that Sabrina had in the end is repeated. Make the number of coins that Sabrina had in the end the same. LCM of 1 and 2 is 2.
Number of coins that Mary had at first = 6 u
Number of coins that Mary had more than Sabrina at first
= 6 u - 3 u
= 3 u
3 u = 12
1 u = 12 ÷ 3 = 4
Number of coins that Sabrina had at first
= 3 u
= 3 x 4
= 12
Answer(s): 12
