One way to improve the fuel efficiency of a car is to use tires that have a lower rolling resistance—tires that roll with less resistance. Highway tests at 65 mph showed that tires with the lowest rolling resistance can improve fuel efficiency by nearly 2 mpg (miles per gallon). Consider a car that gets 35 mpg on high-rolling-resistance tires and is driven 15,000 miles per year. For a fuel cost of $3.5/gal, determine how much money will be saved per year by switching to low-rolling-resistance tires.

It will be saved $81 per year.

Explanation: A car without the tires, that gets 35mpg and is driven 15,000 miles per year, will have a fuel cost of:

1 gal ---- 35 miles

x gal ---- 15,000 miles

x =

x = 428.57 gal

Per year, 1 gal costs $3.5, then:

cost = 428.57*3.5

cost = 1500

The car with the tires, improve the efficiency in nearly 2mpg, i.e.:

efficiency = 35 + 2 = 37mpg

1 gal ----- 37 miles

y gal ----- 15,000 miles

y =

y = 405.40 gal

Per year:

cost = 405.40*3.5

cost = 1419

The difference in costs is:

d = 1500 - 1419

d = 81

With lowest rolling resistance tires, a car will save, per year, $81.

the warning light flashes for a second or two when the engine starts. if it stays on, there's must be something wrong with the coolant. you should never dare to continue driving when the light is on. pull over as soon as possible and shut the engine off.

hope this is what you're talking about