Xylium had some pen collection.
12 of them were black and the rest were yellow. She gave away 186 of the yellow pens and 20% of the black pens. She then had
18 of her pen collection left. How many pens did Xylium give away?
| |
Black |
Yellow |
Total |
Total |
Before
|
1x4 =
4 u |
1x4 =
4 u |
2x4 =
8 u |
8x1 =
8 u |
Change
|
- 0.2x4 =
- 0.8 u |
- 186 |
|
- 7x1 =
- 7 u |
After
|
0.8x4 =
3.2 u |
4 u - 186 |
|
1x1 =
1 u |
The total number of pens that Xylium had at first is repeated. Make the total number of pens at first the same. LCM 2 and 8 is 8.
Number of black pens that Xylium gave away
= 20% x 1 u
=
20100 x 1 u
= 0.2 u
0.8 u - 186 = 7 u
7 u - 0.8 u = 186
6.2 u = 186
1 u = 186 ÷ 6.2 = 30
Number of pens that Xylium gave away
= 7 u
= 7 x 30
= 210
Answer(s): 210
