Question

While traveling along a highway a driver slows from 24 m/s to 15 m/s in 12 seconds. What is the automobile’s acceleration? (Remember that a negative value indicates a slowing down or deceleration.)

Answer 1

I don't get it what does m/s mean its

r= t/d Rate, time, and distance 
time 30min distance 5miles divide 30 = 6 rate is 5 miles every 6min  I think

I don't understand but that's how you calculate rate :P