Exercise Frequency
1. **State the problem:** We are given a pie chart representing 120 gym members' daily exercise amounts. The chart sections are:
- 162° for "< 30 minutes"
- 108° for "30 - 60 minutes"
- The remaining angle for "> 60 minutes"
We need to find:
a) How many members exercise at least 30 minutes each day?
b) Why a newspaper's claim that most people do this might be incorrect.
2. **Calculate total degrees of a circle:**
The total degrees in a pie chart are always $360^\circ$.
3. **Find the angle of the "> 60 minutes" sector:**
$$360^\circ - 162^\circ - 108^\circ = 90^\circ$$
4. **Find the fraction of members for each exercise category:**
- For "< 30 minutes": $\frac{162}{360} = \frac{9}{20}$
- For "30 - 60 minutes": $\frac{108}{360} = \frac{3}{10}$
- For "> 60 minutes": $\frac{90}{360} = \frac{1}{4}$
5. **Calculate the number of members for each category:**
- "< 30 minutes": $120 \times \frac{9}{20} = 54$
- "30 - 60 minutes": $120 \times \frac{3}{10} = 36$
- "> 60 minutes": $120 \times \frac{1}{4} = 30$
6. **Answer part (a):**
Members doing at least 30 minutes means those doing "30 - 60 minutes" or "> 60 minutes":
$$36 + 30 = 66$$
So, \textbf{66 members say they exercise at least 30 minutes daily}.
7. **Answer part (b):**
The newspaper's claim that most people in the country exercise at least 30 minutes daily is incorrect because:
- The data is only from gym members, not the whole country.
- This group may be more active than the average population.
- It’s a specific sample, not representative of general population habits.
Thus, generalizing these results to the entire country is misleading.