The number of $10, $20 and $50 notes in a piggy bank is in the ratio of 1 : 2 : 1. The notes are worth $900 altogether. Find the total number of $20 and $50 notes.
| |
$10 |
$20 |
$50 |
Total |
| Number |
1 u |
2 u |
1 u |
|
| Value |
$10 |
$20 |
$50 |
|
| Total value |
10 u |
40 u |
50 u |
$900 |
Total value of $10, $20 and $50 notes
= 10 u + 40 u + 50 u
= 100 u
100 u = 900
1 u = 900 ÷ 100 = 9
Number of $20 and $50 notes
= 2 u + 1 u
= 3 u
= 3 x 9
= 27
Answer(s): 27
