The number of $5, $10 and $20 notes in a piggy bank is in the ratio of 5 : 9 : 7. The notes are worth $2040 altogether. Find the total number of $10 and $20 notes.
| |
$5 |
$10 |
$20 |
Total |
| Number |
5 u |
9 u |
7 u |
|
| Value |
$5 |
$10 |
$20 |
|
| Total value |
25 u |
90 u |
140 u |
$2040 |
Total value of $5, $10 and $20 notes
= 25 u + 90 u + 140 u
= 255 u
255 u = 2040
1 u = 2040 ÷ 255 = 8
Number of $10 and $20 notes
= 9 u + 7 u
= 16 u
= 16 x 8
= 128
Answer(s): 128
