MATHS - Ratio - Inverse Proportion

This video tutorial explains inverse proportion, contrasting it with direct proportion. It uses examples like car speeds and cleaning scenarios to illustrate how inverse proportion works, where one quantity increases as the other decreases, maintaining a constant product. The video also covers mathematical representations, including equations and constants of proportionality, and explores inverse proportion involving indices. It concludes with methods to find values of variables in inverse proportion equations.

What happens to the time taken to travel a fixed distance if the speed of a car is doubled?

• The time is doubled.

• The time is tripled.

• The time is halved.

• The time remains the same.

If 5 cleaners take 3 hours to clean a building, how long will it take 3 cleaners to do the same job?

• 15 hours

• 3 hours

• 5 hours

• 9 hours

In inverse proportion, what does the constant of proportionality, k, represent?

• The sum of the two quantities

• The ratio of the two quantities

• The difference between the two quantities

• The product of the two quantities

How do you express y in terms of x if y is inversely proportional to x and k is 210?

• y = x / 210

• y = 210 - x

• y = 210x

• y = 210 / x

What is the value of y when x = 15, given that y is inversely proportional to x with k = 210?

• 14

• 15

• 16

• 17

If y is inversely proportional to the square of x, and y = 20 when x = 3, what is the value of y when x = 2?

• 45

• 60

• 30

• 20

For the equation y = 180 / x^2, what is the value of x when y = 7.2?

• 6

• 3

• 4

• 5