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# A school has 8 periods a day each of 45 minutes of duration. How long would each period be, if the school has 9 periods a day assuming the number of school hours to be the same?

**Solution:**

Consider x to be the number of periods and y as the duration of each period.

Let x₁ = 8, y₁ = 45, x₂ = 9, y₂ = ?

If the number of period increase, then the duration of per period will decrease. So, it is inverse variation.

Two numbers x and y are said to be in inverse proportion when an increase in one quantity decreases the other quantity and vice versa.

xy = k or x = (1/y) k

where k is a constant.

Hence, x₁y₁ = x₂y₂

8 × 45 = 9 × y₂

y₂_{ }= (8 × 45)/9

y₂_{ }= 40

Thus, each period would be 40 minutes long.

**☛ Check: **NCERT Solutions for Class 8 Maths Chapter 13

**Video Solution:**

## A school has 8 periods a day each of 45 minutes of duration. How long would each period be, if the school has 9 periods a day assuming the number of school hours to be the same?

NCERT Solutions Class 8 Maths Chapter 13 Exercise 13.2 Question 11

**Summary:**

A school has 8 periods a day each of 45 minutes of duration. If the school has 9 periods a day assuming the number of school hours to be the same, each period would be 40 minutes long.

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