NBT Quantitative Literacy: Charts, Tables and Graphs Flashcards

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:

Answer: R239

Extra minutes = 50; extra cost = 50 × R0.80 = R40; total = R199 + R40 = R239.

A pie chart shows spending: food 45%, rent 30%, transport 15%, and savings 10%. If total income is R8 000, how much is saved?

Answer: R800

10% of R8 000 = R800.

A line graph has a steeper gradient between points A and B than between B and C. What does this indicate?

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.

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?

Answer: 30

Males preferring coffee = 110 total males − 80 who prefer tea = 30.

A histogram is different from a bar chart because:

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.

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)?

Answer: Mean

The mean is calculated using all values, so an extreme outlier directly changes it; median and mode are resistant to outliers.

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:

Answer: All classes equally

All four classes have the same frequency (5 each), so all are equally the modal class.