In an envelope, there were a total of 432 notes. 75% of them were $10-notes. The rest were $50-notes. Billy took out some $10-notes. As a result, the remaining $10-notes made up 10% of the notes left in the envelope. Find the total value of the $10-notes Billy took out from the envelope.
|
$10 |
$50 |
Total |
Before |
3x9 = 27 u |
1x9 = 9 u |
4x9 = 36 u |
Change |
- ? |
|
|
After |
1x1 = 1 u |
9x1 = 9 u |
10x1 = 10 u |
75% =
75100 =
34
10% =
10100 =
110
The number of $50-notes remains unchanged. Make the number of $50-notes the same. LCM of 1 and 9 is 9.
Total number of notes at first = 36 u
36 u = 432
1 u = 432 ÷ 36 = 12
Number of $10-notes that Billy took out from the envelope
= 27 u - 1 u
= 26 u
= 26 x 12
= 312
Total value of $10-notes taken out
= 312 x 10
= $3120
Answer(s): $3120