In an envelope, there were a total of 280 notes. 70% of them were $100-notes. The rest were $1-notes. Tommy took out some $100-notes. As a result, the remaining $100-notes made up 30% of the notes left in the envelope. Find the total value of the $100-notes Tommy took out from the envelope.
| |
$100 |
$1 |
Total |
| Before |
7x7 =
49 u |
3x7 =
21 u |
10x7 =
70 u |
| Change |
- ? |
|
|
| After |
3x3 =
9 u |
7x3 =
21 u |
10x3 =
30 u |
70% =
70100 =
710
30% =
30100 =
310
The number of $1-notes remains unchanged. Make the number of $1-notes the same. LCM of 3 and 7 is 21.
Total number of notes at first = 70 u
70 u = 280
1 u = 280 ÷ 70 = 4
Number of $100-notes that Tommy took out from the envelope
= 49 u - 9 u
= 40 u
= 40 x 4
= 160
Total value of $100-notes taken out
= 160 x 100
= $16000
Answer(s): $16000
