Sarah had some coin collection.
25 of them were grey and the rest were blue. She gave away 113 of the blue coins and 20% of the grey coins. She then had
16 of her coin collection left. How many coins did Sarah give away?
|
Grey |
Blue |
Total |
Total |
Before
|
2x6 = 12 u |
3x6 = 18 u |
5x6 = 30 u |
6x5 = 30 u |
Change
|
- 0.4x6 = - 2.4 u |
- 113 |
|
- 5x5 = - 25 u |
After
|
1.6x6 = 9.6 u |
18 u - 113 |
|
1x5 = 5 u |
The total number of coins that Sarah had at first is repeated. Make the total number of coins at first the same. LCM 5 and 6 is 30.
Number of grey coins that Sarah gave away
= 20% x 2 u
=
20100 x 2 u
= 0.4 u
2.4 u - 113 = 25 u
25 u - 2.4 u = 113
22.6 u = 113
1 u = 113 ÷ 22.6 = 5
Number of coins that Sarah gave away
= 25 u
= 25 x 5
= 125
Answer(s): 125