Resolve the problem. Justify your answer, using the formulas of both arithmetic progression and geometric progression. Jaime and Rafael are dedicated to painting houses. Jaime quotes $24 for the first hour and then adds $2.85 for each hour of work. In this way, the second hour is charged at $26.85 and so on. On the other hand, Rafael quotes $1.50 for the first hour and then doubles the cost per hour. After a 7-hour work day. What type of progression does each painter's hourly rate represent? Who would earn more, adding a total of 7 hours of work?
Question
Answer:
*1. Identify the type of progression for each painter:*
Jaime:
- First hour: $24
- Second hour: $24 + $2.85 = $26.85
- Third hour: $26.85 + $2.85 = $29.70
... and so on.
The difference between consecutive terms is constant, which is $2.85. Thus, Jaime's hourly rate represents an *arithmetic progression (AP)*.
Rafael:
- First hour: $1.50
- Second hour: $1.50 Γ 2 = $3
- Third hour: $3 Γ 2 = $6
... and so on.
The ratio between consecutive terms is constant, which is 2. Thus, Rafael's hourly rate represents a *geometric progression (GP)*.
*2. Calculate the total earnings for each painter for 7 hours using the formulas for AP and GP:*
For Jaime (AP):
Sn = (n/2) (2a + (n-1)d)
Where:
Sn is the sum of the first n terms
n is the number of terms (7 in this case)
a is the first term $24
d is the common difference $2.85
\[ S_7 = \frac{7}{2} (2(24) + (7-1)(2.85)) \]
\[ S_7 = \frac{7}{2} (48 + 17.1) \]
S7 = 7/2 Γ 65.1 = 227.85
For Rafael (GP):
Sn = a ((r^n) - 1)/(r - 1)
Where:
Sn) is the sum of the first n terms
n is the number of terms (7 in this case)
a is the first term ($1.50)
r is the common ratio (2)
S7 = 1.5 ((2^7) - 1)/(2 - 1)
S7 = 1.5 Γ (127) = 190.5
*3. Compare the total earnings:*
Jaime: $227.85
Rafael: $190.5
*Conclusion:*
- Jaime's hourly rate represents an arithmetic progression.
- Rafael's hourly rate represents a geometric progression.
- After a 7-hour workday, Jaime would earn more with a total of $227.85 compared to Rafael's $190.5.
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11 months ago
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