Question

Car A travels at 45 miles per hour and Car B travels at a greater speed of x miles per hour. Right and simplify an expression that represents how many miles further Cardi B travels in two hours.

Answer 1

`2\; x` miles.

Explanation:

What's the speed of car B?

`v_B = v_a + x = 45 + x` miles per hour.

How far does each car travel in two hours?

`s = v \cdot t`.

• 
  `s_A = v_A \cdot t = 2 * 45 = 90` miles.
• 
  `s_B = v_B \cdot t = 2 * (45 + x) = 90 + 2\;x` miles.

How many miles further does car B travel in two hours than car A?

`s_B - s_A = (90 + 2 \; x) - 90 = 90 - 90 + 2\; x = 2 \; x` miles.