81) A large school district has 300 school buses. If each school bus is used 3.0 hours each day,
the average speed of the school buses is 15 mi/h, and the fuel economy of the buses is 10 mi/gal.
How much does it cost to run these buses for 22 school days if gasoline costs $4.10 a gallon?
A) $60,000
B) $120,000
C) $180,000
D) $240,000
82) A 2.00-qt bottle of soda is on sale for $1.29. What should be the price of a 2.00-L bottle of
the same soda to yield the same value? (1.00 qt = 0.947 L)
83) In a country where the unit of currency is the Passi, kerosene costs 130 Passi per liter, and
one dollar buys 227 Passi. What is the cost of kerosene in dollars per gallon? (1.00 gal = 3.79 L)
84) The tank of a certain car holds 16 gallons of gasoline. (1.00 gal = 3.785 L)
(a) How many liters of gasoline does this tank hold?
(b) How many kilometers can the car travel on one tank if it gets 25 miles per gallon?
85) The mass of Mars, 6.40 × 1023 kg, is about one-tenth that of Earth, and its radius, 3395 km,
is about half that of Earth. What is the mean density (mass divided by volume) of Mars in
kilograms per cubic meter?
A) 9.76 × 102 kg/m3
B) 1.95 × 103 kg/m3
C) 3.90 × 103 kg/m3
D) 7.81 × 103 kg/m3
86) The average density of blood is 1.06 × 103 kg/m3. If you donate a pint of blood to the Red
Cross, how many grams of blood have you donated? (2.00 pt = 1.00 qt, 1.00 L = 1000 cm3, 1.00
qt = 0.947 L, and density is mass per unit volume.)
A) 502 g
B) 0.502 g
C) 5020 g
D) 5.02 × 105 g
E) 5.02 g