The time t required to drive afixed distance varies inversely as the speed r. It takes 5 hr at a speed of 80 km/h to drive a fixed distance. How long will it take t odrive the same distance at a speed of 70 km/hr?

Please help!

In an inverse dependence situation, the product of the two variables is a constant. In this rase, r x t = constant

Therefore
5 hr x 80 km/h = t x 70 km/h

t = (80/70) x 5 h = 5.714 hr
= 5 hr 42.9 min

To solve this problem, we can use the concept of inverse variation. Inverse variation means that as one variable increases, the other variable decreases, and the product of the two variables remains constant.

In this case, the time required to drive a fixed distance (t) varies inversely with the speed (r). This can be represented by the equation t = k/r, where k is the constant of variation.

We are given that it takes 5 hours (t) to drive a fixed distance at a speed of 80 km/h (r). Let's use this information to find the value of k.

5 = k/80

To solve for k, we can cross-multiply and then divide both sides by 80:

5 * 80 = k
k = 400

Now, we can use the value of k to find the time it will take to drive the same distance at a speed of 70 km/h.

t = 400/70

Calculating this, we find:

t ≈ 5.714 hours

This can also be expressed as 5 hours and 42.9 minutes. Therefore, it will take approximately 5 hours and 42.9 minutes to drive the same distance at a speed of 70 km/h.