Question

the driving time varies inversely with the speed of the car. if a certain trip takes 40 minutes when you travel 50 miles per hour, how many minutes would it take if you travel 40 miles per hour?

Explanation:

Step1: Set up the inverse - variation formula

Let $t$ be the driving time and $s$ be the speed. The inverse - variation formula is $t_1s_1=t_2s_2$.

Step2: Convert the given values to consistent units

We have $t_1 = 40$ minutes, $s_1=50$ miles per hour, and $s_2 = 40$ miles per hour. Substitute into the formula: $40\times50=t_2\times40$.

Step3: Solve for $t_2$

Divide both sides of the equation $40\times50=t_2\times40$ by 40. So, $t_2=\frac{40\times50}{40}=50$ minutes.

Answer:

50