HSN.Q Tutor Intake -- Units, Quantities, and Accuracy

A factory produces widgets at a rate of 150 widgets per hour.
Each widget uses 0.5 kg of raw material. The factory runs for
8 hours. A student wants to find the total kilograms of raw
material used. Before computing, which unit analysis shows that
multiplication of all three quantities gives kilograms?

Two neighborhoods are being compared for income per resident.
Neighborhood A has a total annual income of $5,000,000 and a
population of 500 people. Neighborhood B has a total annual income
of $3,000,000 and a population of 200 people.
Compute the per-capita income (dollars per resident) for
Neighborhood B. Enter a number.

A digital scale is calibrated to read exactly 0 g when empty.
A technician measures a 100.000 g reference mass five times and
records: 102.3 g, 102.4 g, 102.3 g, 102.3 g, 102.4 g.
Which statement correctly describes these measurements?

A student needs to convert 45 miles per hour to meters per second.
Known equivalences: 1 mile = 1,609 meters; 1 hour = 3,600 seconds.
Which dimensional analysis chain is set up correctly so that
unwanted units cancel and meters/second remains?

A car travels at 60 miles per hour. Convert this speed to
kilometers per hour. Use the fact that 1 mile = 1.609 km.
Round your answer to the nearest whole number.

The formula for distance is $d = r \times t$, where $r$ is speed
in km/h and $t$ is time. A car travels at $r = 80$ km/h. A student
is given $t = 90$ minutes and computes $d = 80 \times 90 = 7{,}200$.
What is wrong with this calculation?

How many significant figures does the measurement 0.00470 km
contain?

A rectangle is measured as 4.2 m wide and 6.84 m long.
Using significant figure rules for multiplication, what should
the area be reported as? Enter a number (in m²).

A student adds two measured lengths: 1,000 m (measured to the
nearest meter) and 1.23 m (measured to the nearest 0.01 m).
Applying the correct significant-figure rule for addition, what
should the sum be reported as?