A teacher grades 25 students essays in 4 hours. Assuming he grades at the same speed, how long will it take him to grade 35 essays?

What is the constant of this variation?

For this case, the first thing we must do is define a variable:

x: number of hours

y: number of trials

We write the equation that represents the problem:

y = (25/4) x

For 35 essays we have:

35 = (25/4) x

Clearing x:

x = 5.6 hours

Answer:

it will take him to grade 35 essays а bout:

x = 5.6 hours

the constant of this variation is:

25/4 essays / hour