College

Hayden and Nate have decided to begin preparing for their final exams 15 weeks ahead of the exam date. Hayden starts by studying for 12 hours in the first week and plans to increase the amount by 2 hours each week. Nate starts by studying 12 hours in the first week and plans to increase the amount he studies by 10% every week.

A. Write explicit rules to describe the study time for Hayden and for Nate.

B. How many hours did each student study in week 8?

C. How many hours in total does each boy study for the entire 15 weeks?

D. In which week will Nate catch up to Hayden in the number of hours spent on studying?

Answer :

The explicit rules for Hayden and Nate are y = 12 + 2 * (x - 1) and [tex]y = 12 \times (1 + 0.1)^{(\text{x} - 1)}[/tex]

Hayden studied for 26 hours and Nate for 23.4 hours

Total study hours for each boy over 15 weeks are 390 and 381.6

The week number when Nate catches up to Hayden is 1

A. Explicit rules for Hayden and Nate:

Let the week number be x

So, we have

For Hayden:

y = 12 + 2 * (x - 1)

For Nate:

[tex]y = 12 \times (1 + 0.1)^{(\text{x} - 1)}[/tex]

B. Number of hours each student studied in week 8:

Here, we set x = 8

So, we have

For Hayden:

[tex]\[ \text{y} = 12 + 2 \times (8 - 1) = 12 + 2 \times 7 = 12 + 14 = 26 \text{ hours} \][/tex]

For Nate:

[tex]\[ \text{y} = 12 \times (1 + 0.1)^{(8 - 1)} = 12 \times (1.1)^7 \][/tex]

[tex]\[ \text{y} \approx 12 \times 1.948717 = 23.4\text{ hours} \][/tex]

C. Total study hours for each boy over 15 weeks:

For Hayden: we have

[tex]\[ \text{Total} = \sum_{n=1}^{15} (12 + 2 \times (n - 1)) \][/tex]

Using the sum of AP series, we have

[tex]\[ \text{Total} = \dfrac{15}{2}(2 \times 12 + (15 - 1) \times 2)[/tex]

Evaluate

[tex]\[ \text{Total} = 390[/tex]

For Nate:

[tex]\[ \text{Total} = \sum_{n=1}^{15} (12 \times (1 + 0.1)^{n - 1}) \][/tex]

[tex]\[ \text{Total} = \sum_{n=1}^{15} (12 \times (1 .1)^{n - 1}) \][/tex]

Using the sum of GP, we have

[tex]\[ \text{Total} = \dfrac{12 \times (1 .1)^{15} - 1}{1.1 - 1} \][/tex]

Evaluate

[tex]\[ \text{Total} = \dfrac{12 \times 3.18}{14} \][/tex]

[tex]\[ \text{Total} = 381.6[/tex]

D. Week when Nate catches up to Hayden in study hours:

This is represented as

[tex](12 \times (1.1)^{x - 1}) = (12 + 2 \times (x - 1))[/tex]

Solving graphically, we have

x = 1

This mean sthat

The week number when Nate catches up to Hayden is 1

A. Hayden: [tex]\(S_H(n) = 12 + 2(n-;1)\)[/tex] Nate: [tex]\(S_N(n) = 12(1 + 0.10)^{n-1}\)[/tex]

B. Hayden: 26 hours ; Nate: approximately 25.94 hours.

C. Hayden: 600 hours ; Nate: approximately 1168.46 hours.

D. Nate catches up to Hayden in week 16.

A.

1. For Hayden: The explicit rule for Hayden's study time can be described as [tex]\(S_H(n) = 12 + 2(n-1)\),[/tex] where (n) represents the week number.

2. For Nate: The explicit rule for Nate's study time can be described as

[tex]\(S_N(n) = 12(1 + 0.10)^{n-1}\),[/tex] where (n) represents the week number.

B. To find out how many hours each student studied in week 8:

1. For Hayden: [tex]\(S_H(8) = 12 + 2(8-1) = 12 + 14 = 26\)[/tex] hours.

2. For Nate: [tex]\(S_N(8) = 12(1 + 0.10)^{8-1} = 12(1.10)^7 \approx 25.94\)[/tex] hours.

C. To find out how many hours each boy studied in the entire 15 weeks:

1. For Hayden [tex]: \(S_H(15) = 12 + 2(15-1) = 12 + 28 = 40\)[/tex] hours per week. Therefore, [tex]\(40 \times 15 = 600\)[/tex] hours in total.

2. For Nate: [tex]\(S_N(15) = 12(1 + 0.10)^{15-1} = 12(1.10)^{14} \approx 77.90\)[/tex] hours per week. Therefore, [tex]\(77.90 \times 15 \approx 1168.46\)[/tex] hours in total.

D. To find out in which week Nate will catch up to Hayden in the number of hours spent on studying:

We set [tex](S_N(n) = S_H(n)\)[/tex] and solve for (n):

[tex]\[12(1.10)^{n-1} = 12 + 2(n-1)\]\[1.10^{n-1} = \frac{12 + 2(n-1)}{12}\]\[1.10^{n-1} = 1 + \frac{n-1}{6}\]\[1.10^{n-1} = \frac{n + 5}{6}\][/tex]

Taking the natural log of both sides:

[tex]\[n-1 = \log_{1.10}\left(\frac{n+5}{6}\right)\]\[n = \log_{1.10}\left(\frac{n+5}{6}\right) + 1\][/tex]

Using numerical methods or software, we find [tex]\(n \approx 15.72\).[/tex]

Since (n) must be an integer, Nate will catch up to Hayden in week 16.