Mark has 10 notes. There are only two-dollar notes and twenty-dollar notes. The total amount of money is $74. How many twenty-dollar notes does Mark have?
Number of
twenty-dollar notes |
Value of
twenty-dollar notes |
Number of
two-dollar notes |
Value of
two-dollar notes |
Total
value |
| 10 |
10 x 20 = $200 |
0 |
0 |
$200 |
| 9 |
9 x 20 = $180 |
1 |
1 x 2
= $2 |
$182 |
| 3 |
3 x 20 =
$60 |
7 |
7 x 2 = $14 |
$74 |
Total amount of money if all the notes are twenty-dollar notes
= 10 x 20
= $200
Big difference between the amounts of twenty-dollar notes and two-dollar notes
= 200 - 74
= $126
Small difference between amount in one twenty-dollar note and one two-dollar note
= 20 - 2
= 18
Number of two-dollar notes
= 126 ÷ 18
= 7
Number of twenty-dollar notes
= 10 - 7
= 3
Answer(s): 3
