In an envelope, there were a total of 280 notes. 60% of them were $2-notes. The rest were $50-notes. Riordan took out some $2-notes. As a result, the remaining $2-notes made up 30% of the notes left in the envelope. Find the total value of the $2-notes Riordan took out from the envelope.
|
$2 |
$50 |
Total |
Before |
3x7 = 21 u |
2x7 = 14 u |
5x7 = 35 u |
Change |
- ? |
|
|
After |
3x2 = 6 u |
7x2 = 14 u |
10x2 = 20 u |
60% =
60100 =
35
30% =
30100 =
310
The number of $50-notes remains unchanged. Make the number of $50-notes the same. LCM of 2 and 7 is 14.
Total number of notes at first = 35 u
35 u = 280
1 u = 280 ÷ 35 = 8
Number of $2-notes that Riordan took out from the envelope
= 21 u - 6 u
= 15 u
= 15 x 8
= 120
Total value of $2-notes taken out
= 120 x 2
= $240
Answer(s): $240