In an envelope, there were a total of 450 notes. 80% of them were $5-notes. The rest were $100-notes. Billy took out some $5-notes. As a result, the remaining $5-notes made up 10% of the notes left in the envelope. Find the total value of the $5-notes Billy took out from the envelope.
| |
$5 |
$100 |
Total |
| Before |
4x9 =
36 u |
1x9 =
9 u |
5x9 =
45 u |
| Change |
- ? |
|
|
| After |
1x1 =
1 u |
9x1 =
9 u |
10x1 =
10 u |
80% =
80100 =
45
10% =
10100 =
110
The number of $100-notes remains unchanged. Make the number of $100-notes the same. LCM of 1 and 9 is 9.
Total number of notes at first = 45 u
45 u = 450
1 u = 450 ÷ 45 = 10
Number of $5-notes that Billy took out from the envelope
= 36 u - 1 u
= 35 u
= 35 x 10
= 350
Total value of $5-notes taken out
= 350 x 5
= $1750
Answer(s): $1750
