Someone help me on letter b please! I’m having trouble with with this!

Which of the fallowing best completes the sequence 5,10,15, a) 30 b) 22 c)25 d)35

Acar started driving from city a to city b, distance between which is 620 miles, at a rate of 60 mph. two hours later a truck left city b and started moving towards city a at a rate of 40 mph. how many hours after the truck's departure will the two meet?

Solve each equation using the quadratic formula. find the exact solutions. 6n^2 + 4n - 11