Solutions: Bar Graphs (Section 4.3)

Page 86: Figure it Out (Class Attendance)

Refer to the bar graph on page 86 of the text.

• Class 1: 3 absent
• Class 2: 5 absent
• Class 3: 4 absent
• Class 4: 2 absent
• Class 5: 0 absent
• Class 6: 1 absent
• Class 7: 5 absent
• Class 8: 7 absent

Answers:

1. In Class 2, 5 students were absent.
2. In which class were the maximum number of students absent? Class 8.
3. Which class had full attendance (0 absent)? Class 5.

Page 88: Figure it Out (Traffic Crossing)

Q1. How many total cars passed through the crossing between 6 a.m. and noon? Using the graph:

• 6-7 am: 150
• 7-8 am: 1200
• 8-9 am: 1000
• 9-10 am: 900
• 10-11 am: 600 (Estimated from graph description)
• 11-12 pm: 600 (Text says “about 600” for 11-12).
• Note: The text explicitly calculates 8-10am as 1800. Summing all bars: $150 + 1200 + 1000 + 900 + 600 + 600 = 4450$. Ans: 4450 cars.

Q2. Why little traffic 6-7 am? Ans: Most offices and schools start later (around 8 or 9 am), so fewer people are commuting that early.

Q3. Why heaviest traffic 7-8 am? Ans: This is the peak rush hour when school buses and office goers are travelling.

Q4. Why lesser traffic after 8 am? Ans: Once the school/office start times pass, the rush decreases.