Tom and Sam have some grey pens and some brown pens. The number of brown pens Tom has is equal to the number of grey pens Sam has.
23 of Tom's pens are grey and
13 of Sam's pens are brown. There are a total of 60 grey pens. Find the total number of pens they have.
| Tom |
Sam |
Total |
| Grey |
Brown |
Grey |
Brown |
|
| |
1x2 |
1x2 |
|
|
| 2x2 |
1x2 |
2x1 |
1x1 |
|
| 4 u |
2 u |
2 u |
1 u |
9 u |
The number of Tom's brown pens and Sam's grey pens is the same.
The number of Tom's brown pens is repeated. The number of Sam's grey pens is repeated. Make the number of Tom's brown pens and Sam's grey pens the same. LCM of 1 and 3 is 2.
Number of grey pens
= 4 u + 2 u
= 6 u
6 u = 60
1 u = 60 ÷ 6 = 10
Total number of pens
= 4 u + 2 u + 2 u + 1 u
= 9 u
= 9 x 10
= 90
Answer(s): 90
