Answer:
This is direct variation.
Step-by-step explanation:
The direct variation is a relationship between two variables that are related by a proportionality constant.
It can be written as y=kx ; where k is proportionality constant .
In inverse variation the product of two variables is equal to a constant.
Given statement here is :
The number of tons of coal burned by an old coal burning locomotive under given conditions varies as the number of hours.
This is direct variation as the more the train runs, the more coal is used.
Let number of tons of coal be = t
Let the number of hours be = h
So, we can relate this as :
't' can be calculated if you know the constant k.