The number of $10, $20 and $100 notes in a piggy bank is in the ratio of 5 : 4 : 2. The notes are worth $3960 altogether. Find the total number of $10 and $20 notes.
|
$10 |
$20 |
$100 |
Total |
Number |
5 u |
4 u |
2 u |
|
Value |
$10 |
$20 |
$100 |
|
Total value |
50 u |
80 u |
200 u |
$3960 |
Total value of $10, $20 and $100 notes
= 50 u + 80 u + 200 u
= 330 u
330 u = 3960
1 u = 3960 ÷ 330 = 12
Number of $10 and $20 notes
= 5 u + 4 u
= 9 u
= 9 x 12
= 108
Answer(s): 108