Betty had some marble collection.
34 of them were brown and the rest were black. She gave away 132 of the black marbles and 50% of the brown marbles. She then had
16 of her marble collection left. How many marbles did Betty give away?
| |
Brown |
Black |
Total |
Total |
Before
|
3x3 =
9 u |
1x3 =
3 u |
4x3 =
12 u |
6x2 =
12 u |
Change
|
- 1.5x3 =
- 4.5 u |
- 132 |
|
- 5x2 =
- 10 u |
After
|
1.5x3 =
4.5 u |
3 u - 132 |
|
1x2 =
2 u |
The total number of marbles that Betty had at first is repeated. Make the total number of marbles at first the same. LCM 4 and 6 is 12.
Number of brown marbles that Betty gave away
= 50% x 3 u
=
50100 x 3 u
= 1.5 u
4.5 u - 132 = 10 u
10 u - 4.5 u = 132
5.5 u = 132
1 u = 132 ÷ 5.5 = 24
Number of marbles that Betty gave away
= 10 u
= 10 x 24
= 240
Answer(s): 240
