Risa had a total of 133 pieces of $10 and $50 notes at first. She spent
27 of the number of $10 notes and received another 11 pieces of $50 notes from her mother. After that, the number of $50 notes she had was
12 of the remaining notes. How much money did Risa have at first?
|
$10 |
$50 |
Total |
Before |
7 u |
5 u - 11 |
133 |
Change |
- 2 u |
+ 11 |
|
After |
5 u |
|
|
Comparing $10-notes and $50-notes |
1x5 = 5 u |
1x5 = 5 u |
|
The number of $10-notes and $50-notes in the end is the same.
The number of $10-notes in the end is repeated. Make the number of $10-notes in the end the same. LCM of 1 and 5 is 5.
Number of notes at first
= 7 u + 5 u - 11
= 12 u - 11
12 u - 11 = 133
12 u = 133 + 11
12 u = 144
1 u = 144 ÷ 12 = 12
Number of $10-notes at first
= 7 u
= 7 x 12
= 84
Total value of $10-notes at first
= 84 x 10
= $840
Number of $50-notes at first
= 5 u - 11
= 5 x 12 - 11
= 60 - 11
= 49
Total value of $50-notes at first
= 49 x 50
= $2450
Amount that Risa had at first
= 840 + 2450
= $3290
Answer(s): $3290