Oscar and Paul have some white pens and some black pens. The number of black pens Oscar has is equal to the number of white pens Paul has.
34 of Oscar's pens are white and
16 of Paul's pens are black. There are a total of 100 white pens. Find the total number of pens they have.
| Oscar |
Paul |
Total |
| White |
Black |
White |
Black |
|
| |
1x5 |
1x5 |
|
|
| 3x5 |
1x5 |
5x1 |
1x1 |
|
| 15 u |
5 u |
5 u |
1 u |
26 u |
The number of Oscar's black pens and Paul's white pens is the same.
The number of Oscar's black pens is repeated. The number of Paul's white pens is repeated. Make the number of Oscar's black pens and Paul's white pens the same. LCM of 1 and 4 is 5.
Number of white pens
= 15 u + 5 u
= 20 u
20 u = 100
1 u = 100 ÷ 20 = 5
Total number of pens
= 15 u + 5 u + 5 u + 1 u
= 26 u
= 26 x 5
= 130
Answer(s): 130
