Carl had a total of 42 notes. The notes are $5 notes and $10 notes. After he spent 80% of the $5 notes and 75% of the $10 notes on one television set, he was left with 4 times as many $10 notes as $5 notes. How much did the television set cost?
|
$5 |
$10 |
Before |
5x1 = 5 u |
4x4 = 16 u
|
Change |
- 4x1 = - 4 u |
- 3x4 = - 12 u
|
After |
1x1 = 1 u |
1x4 = 4 u |
Comparing $5 and $10 in the end |
1x1 = 1 u
|
4x1 = 4 u |
80% of $5 notes =
80
100 of $5 notes =
45 of $5 notes
75% of $10 notes =
75100 of $10 notes =
34 of $10 notes
The number of $5 notes in the end is repeated. Make the number of $5 notes the same. LCM of 1 and 4 is 4.
The number of $10 notes in the end is repeated. Make the number of $10 notes the same. LCM of 1 and 1 is 1.
Number of notes at first
= 5 u + 16 u
= 21 u
21 u = 42
1 u = 42 ÷ 21 = 2
|
$5 |
$10 |
Number |
4 u |
12 u |
Value |
5 |
10 |
Total value |
20 u |
120 u |
Value of $5 spent
= 4 u x 5
= 20 u
Value of $10 spent
= 12 u x 10
= 120 u
Price of the television set
= 20 u + 120 u
= 140 u
= 140 x 2
= $280
Answer(s): $280