Question

You are driving in a foreign country and you see a sign showing a speed limit of 60 km/hr. What is that speed in miles per hour?

Answer 1

Hint: We have to convert the speed from km/hr to miles per hour. It is a very simple arithmetic problem. We know that the speed in km per hour is directly proportional to the speed in miles per hour. 1 mile is equal to 1.61 km.

Complete step-by-step answer:
We have to convert 60 km per hour to miles per hour, we know that speed in km per hour is directly proportional to the speed in miles per hour
We know that 1 mile is equal to 1.61 km so the proportionality constant is equal to 1.61
Let’s take 60 km per hour is equal to x miles per hour
So we can write $\dfrac{60}{x}$ is equal to 1.61 , the value of x is equal to $\dfrac{60}{1.61}$ which is equal to 37.21
So we can say that 60 km per hour is equal to 37.21 miles per hour.

Note: We can see that the above question is based on directly proportionality. If x is directly proportional then ratio of x and y are always constant that means $\dfrac{x}{y}$ is constant , but if x and y are inversely proportional to each other then their product of the is constant that means xy is constant.