Chapter 3, Problem 21PTTS

To determine

To write and solve:An inequality to find the number of minutes one can spend on each subject.

Answer to Problem 21PTTS

The inequality is $\Rightarrow 4x\le 135$ and the solution is x=33.75. It means one can spend at most 33 minutes and 45 seconds on 1 subject.

Explanation of Solution

Given information:The maximum time is given = 3 hours.

The time spent on maths is given 45 minutes.

The number of other subjects is given = 4

Also, it is given that the amount of time spent on remaining 4 subjects is same.

Formula used:The concept of forming and solving inequalities is used.

Calculation:

The maximum time is given = 3 hours = 180 minutes.

Let the time spent on other 4 subject be $x$ each.

So, the total time spent is,

  $\Rightarrow 45+4x$ Minutes

And the maximum time is 180 minutes

Hence,

  $\begin{array}{l}\Rightarrow 45+4x\le 180\\ \Rightarrow 4x\le 135\end{array}$

Divide both sides by 4.

  $\Rightarrow x\le 33.75$

Thus, one can spend at most 33 minutes and 45 seconds on 1 subject.