The number of $5, $10 and $20 notes in a piggy bank is in the ratio of 2 : 9 : 3. The notes are worth $1280 altogether. Find the total number of $5 and $10 notes.
| |
$5 |
$10 |
$20 |
Total |
| Number |
2 u |
9 u |
3 u |
|
| Value |
$5 |
$10 |
$20 |
|
| Total value |
10 u |
90 u |
60 u |
$1280 |
Total value of $5, $10 and $20 notes
= 10 u + 90 u + 60 u
= 160 u
160 u = 1280
1 u = 1280 ÷ 160 = 8
Number of $5 and $10 notes
= 2 u + 9 u
= 11 u
= 11 x 8
= 88
Answer(s): 88
