In an envelope, there were a total of 405 notes. 20% of them were $100-notes. The rest were $2-notes. Riordan took out some $100-notes. As a result, the remaining $100-notes made up 10% of the notes left in the envelope. Find the total value of the $100-notes Riordan took out from the envelope.
| |
$100 |
$2 |
Total |
| Before |
1x9 =
9 u |
4x9 =
36 u |
5x9 =
45 u |
| Change |
- ? |
|
|
| After |
1x4 =
4 u |
9x4 =
36 u |
10x4 =
40 u |
20% =
20100 =
15
10% =
10100 =
110
The number of $2-notes remains unchanged. Make the number of $2-notes the same. LCM of 4 and 9 is 36.
Total number of notes at first = 45 u
45 u = 405
1 u = 405 ÷ 45 = 9
Number of $100-notes that Riordan took out from the envelope
= 9 u - 4 u
= 5 u
= 5 x 9
= 45
Total value of $100-notes taken out
= 45 x 100
= $4500
Answer(s): $4500
