Acar is traveling at 30 m/s and about to impact on a wall. what change would result in the safest outcome for the passengers in the car?

An increase in the stopping time (collision time) of the car.

Explanation:

The force exerted on the passenger during the collision is given by:

where is the variation in momentum of the passenger and is the stopping time. From this equation, we see that the force is inversely proportional to the duration of the collision: therefore, if the stopping time is increased (and this is what an airbag does), then the force exerted on the passenger is decreased.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form