Ineed with answer a, b,c i don't get these

A)

if Roy is driving at a speed of "r" miles per hour, so in 1 hour he would have driving 1r and in 2 hours he would have driven 2r.

b)

now, the graduation is 150 miles from his home, BUT he already drove 30 miles, so if he keeps on driving for the next 2 hours, he would have driven then 2r + 30 miles to get to the ceremony, now, by the time he arrives at the ceremony, he already would had covered 150 miles then.  So whatever 2r + 30 is, must be equals or larger than 150, therefore 

c)



check the picture below.

simply means, he needs to drive that fast or faster, to get to the ceremony on time, if it drives that fast(equals), then he'll be there right on time, if he drives faster(greater than) then he'll be there earlier and have enough time to brush his teeth.