Mary's car will go 261 miles on 14.5 gallons of gasoline in highway driving.
a) how many gallons will it take to drive 1641 miles from her house to a friend's house?
b) how far can the car be driven on 139 gallons of gasoline?

a) 91 1/6 gallons

b) 2502 miles

Step-by-step explanation:

You are given a number of miles and a number of gallons for the car. The ratio of these numbers is ...

  (261 mi)/(14.5 gal) = 18 mi/gal

We presume this value is constant for this car. Then the questions can be answered by forming and solving a proportion:

a) 1641 miles/(gallons) = 18 mi/(1 gal)

Multiplying by gallons and dividing by 18 mi/gal, we get

  1641/18 gal = (gallons) = 91 1/6 gal

It will take 91 1/6 gallons of gasoline for Mary to drive to her friend's house.

___

b) Same deal, but the miles are unknown.

  (miles)/(139 gal) = (18 mi)/(1 gal)

Multiplying by 139 gal gives ...

  (18 mi)·139 = (miles) = 2502 mi

139 gallons of gasoline will let Mary drive 2502 miles.

70

step-by-step explanation:

answer: 100

step-by-step explanation: