Basic Mathematics for College Students

Read pictographs.

A pictographis like a bar graph, but the bars are made from pictures or symbols. A
keytells the meaning (or value) of each symbol.

3

7.1 Reading Graphs and Tables 597

StrategyTo answer questions about years, we will locate the correct colored bar
and look at the horizontal axisof the graph. To answer questions about the income,
we will locate the correct colored bar and extend to the left to look at the vertical
axisof the graph.

WHYThe years appear on the horizontal axis. The height of each bar, representing
income in billions of dollars, is measured on the scale on the vertical axis.

Solution

a.The second group of bars indicates income in the year 2000. According to the

color key, the blue bar of that group shows the retail sales. Since the vertical

axis is scaled in units of $250 billion, the height of that bar is approximately

500 plus one-half of 250, or 125. Thus, the height of the blue bar is approximately

500  125 625, which represents $625 billion in retail sales in 2000.

b.In each group, the green bar is the tallest. That bar, according to the color key,
represents the income from the services sector of the economy. Thus, services
consistently generated the most income.
c.According to the color key, the orange bar in each group shows income from
the wholesale sector. That sector generated about $260 billion of income in
1990 and $700 billion in income in 2007. The amount of increase is the
difference of these two quantities.
$700 billion$260 billion$440 billion

Wholesale income increased by about $440 billion between 1990 and 2007.

Subtract the 1990 wholesale income

from the 2007 wholesale income.

500

1,000

1,500

2,000

2,500

Billions of dollars

3,000

3,500

4,000

1990

Wholesale

Retail

Services

Source: The World Almanac, 2004, 2009

2000

Year

2007

National Income by Industry Self Check 3

THE U.S. ECONOMYRefer to the

bar graph of Example 3.

a.What income was generated

by retail sales in 1990?

b.What income was generated

by the wholesale sector in

2007?

c.In 2000, by what amount did

the income from the services

sector exceed the income

from the retail sector?

Now TryProblems 25 and 31

EXAMPLE (^4) Pizza Deliveries
The pictograph on the right shows the
number of pizzas delivered to the three
residence halls on a college campus
during final exam week. In the graph,
what information does the top row of
pizzas give?
Men’s
residence
hall
Women’s
residence
hall
Co-ed
residence
hall
Pizzas ordered during final exam week
= 12 pizzas
Self Check 4
PIZZA DELIVERIESIn the
pictograph of Example 4, what
information does the last row of
pizzas give?
Now TryProblems 33 and 35