If the original quantity is 20 and the new quantity is 18 what is the percent decrease

Liam's parents are driving three times as fast as liam is biking, but they left later than he did. if his parents caught up with him two hours after he left, how much later than liam did they leave?

Every time you drive you will experience a combination of driving conditions and environments.

Write the expression as a constant , a single trigonometric function, or a power of a trigonometric function. sin x cos x/ tan x