In an envelope, there were a total of 128 notes. 75% of them were $10-notes. The rest were $100-notes. Tommy took out some $10-notes. As a result, the remaining $10-notes made up 20% of the notes left in the envelope. Find the total value of the $10-notes Tommy took out from the envelope.
| |
$10 |
$100 |
Total |
| Before |
3x4 =
12 u |
1x4 =
4 u |
4x4 =
16 u |
| Change |
- ? |
|
|
| After |
1x1 =
1 u |
4x1 =
4 u |
5x1 =
5 u |
75% =
75100 =
34
20% =
20100 =
15
The number of $100-notes remains unchanged. Make the number of $100-notes the same. LCM of 1 and 4 is 4.
Total number of notes at first = 16 u
16 u = 128
1 u = 128 ÷ 16 = 8
Number of $10-notes that Tommy took out from the envelope
= 12 u - 1 u
= 11 u
= 11 x 8
= 88
Total value of $10-notes taken out
= 88 x 10
= $880
Answer(s): $880
