Chapter 8.2, Problem 42STP

To determine

To find: The week in which the student will be studying more than 60 mins per week.

A. Week 3      C. Week 5

B. Week 4      D. Week 6

Answer to Problem 42STP

Thus the student will be studying more than 60 mins per week in the 6 weeks that is option D.

Explanation of Solution

Given information:

1^st week 40 min

Increase in study time = 10%

Calculation:

1^st week study time 40 min

Increase in study time = 10%

So 2^nd week study week

  $\begin{array}{l}=40+40\cdot 10\%\\ =40+\frac{40\cdot 10}{100}\\ =40+4\\ =44\end{array}$

Similarly, 3^rdweek study week

  $\begin{array}{l}=44+44\cdot 10\%\\ =40+\frac{44\cdot 10}{100}\\ =44+4.4\\ =44.4\end{array}$

Similarly, 4^thweek study week

  $\begin{array}{l}=44.4+44.4\cdot 10\%\\ =40+\frac{44.4\cdot 10}{100}\\ =44+4.44\\ =48.4\end{array}$

Similarly, 4^th week study week

  $\begin{array}{l}=48.4+48.4\cdot 10\%\\ =48.4+\frac{48.4\cdot 10}{100}\\ =48.4+4.84\\ =53.24\end{array}$

Similarly, 5^thweek study week

  $\begin{array}{l}=53.24+53.24\cdot 10\%\\ =53.24+\frac{53.24\cdot 10}{100}\\ =53.24+5.324\\ =58.564\end{array}$

Similarly, 6^thweek study week

  $\begin{array}{l}=58.564+58.564\cdot 10\%\\ =58.564+\frac{58.564\cdot 10}{100}\\ =58.564+5.8564\\ =64.4204\end{array}$

Thus the student will be studying more than 60 mins per week in the 6 weeks