In an envelope, there were a total of 320 notes. 70% of them were $5-notes. The rest were $1-notes. Ben took out some $5-notes. As a result, the remaining $5-notes made up 20% of the notes left in the envelope. Find the total value of the $5-notes Ben took out from the envelope.
| |
$5 |
$1 |
Total |
| Before |
7x4 =
28 u |
3x4 =
12 u |
10x4 =
40 u |
| Change |
- ? |
|
|
| After |
1x3 =
3 u |
4x3 =
12 u |
5x3 =
15 u |
70% =
70100 =
710
20% =
20100 =
15
The number of $1-notes remains unchanged. Make the number of $1-notes the same. LCM of 3 and 4 is 12.
Total number of notes at first = 40 u
40 u = 320
1 u = 320 ÷ 40 = 8
Number of $5-notes that Ben took out from the envelope
= 28 u - 3 u
= 25 u
= 25 x 8
= 200
Total value of $5-notes taken out
= 200 x 5
= $1000
Answer(s): $1000
