NBT NBT Quantitative Literacy: Charts, Tables and Graphs 4 — Questions and Answers
Question 1: A table shows that a cell phone plan costs R199/month plus R0.80 per minute for calls over 100 minutes. In a month where 150 minutes were used, the total bill is:
- R239 (Correct answer)
- R199
- R319
- R259
Correct answer: R239
Extra minutes = 50; extra cost = 50 × R0.80 = R40; total = R199 + R40 = R239.
Question 2: A pie chart shows spending: food 45%, rent 30%, transport 15%, and savings 10%. If total income is R8 000, how much is saved?
- R800 (Correct answer)
- R1 200
- R400
- R3 600
Correct answer: R800
10% of R8 000 = R800.
Question 3: A line graph has a steeper gradient between points A and B than between B and C. What does this indicate?
- The rate of change was faster between A and B (Correct answer)
- The value was higher between A and B
- No change occurred between B and C
- The value decreased between A and B
Correct answer: The rate of change was faster between A and B
A steeper gradient means a faster rate of change over that interval, regardless of the actual values.
Question 4: A two-way table shows 200 survey responses. 80 males prefer tea, 40 females prefer coffee. If there are 110 males total, how many males prefer coffee?
- 30 (Correct answer)
- 40
- 70
- 80
Correct answer: 30
Males preferring coffee = 110 total males − 80 who prefer tea = 30.
Question 5: A histogram is different from a bar chart because:
- It shows continuous data with no gaps between bars (Correct answer)
- It uses circles instead of bars
- It always has equal bar heights
- It cannot display frequency
Correct answer: It shows continuous data with no gaps between bars
A histogram represents continuous data with bars touching (no gaps), unlike bar charts which show discrete categories.
Question 6: A table shows the number of books read per learner in a class of 30: Mode = 4, Median = 5, Mean = 6. Which measure of central tendency is most affected by an extreme value (outlier)?
- Mean (Correct answer)
- Median
- Mode
- All equally affected
Correct answer: Mean
The mean is calculated using all values, so an extreme outlier directly changes it; median and mode are resistant to outliers.
Question 7: A bar chart shows 5 learners scored in each of the following ranges: 50–59, 60–69, 70–79, 80–89. The modal class is:
- All classes equally (Correct answer)
- 50–59
- 80–89
- 70–79
Correct answer: All classes equally
All four classes have the same frequency (5 each), so all are equally the modal class.
NBT NBT Quantitative Literacy: Charts, Tables and Graphs 4
A table shows that a cell phone plan costs R199/month plus R0.80 per minute for calls over 100 minutes.
In a month where 150 minutes were used, the total bill is: