The number of $5, $10 and $20 notes in a piggy bank is in the ratio of 1 : 1 : 6. The notes are worth $1215 altogether. Find the total number of $5 and $10 notes.
|
$5 |
$10 |
$20 |
Total |
Number |
1 u |
1 u |
6 u |
|
Value |
$5 |
$10 |
$20 |
|
Total value |
5 u |
10 u |
120 u |
$1215 |
Total value of $5, $10 and $20 notes
= 5 u + 10 u + 120 u
= 135 u
135 u = 1215
1 u = 1215 ÷ 135 = 9
Number of $5 and $10 notes
= 1 u + 1 u
= 2 u
= 2 x 9
= 18
Answer(s): 18