GCSE Secondary Maths Age 13-17 - Ratio, Proportion & Rates of Change: Inverse Proportionality - Explained

The video tutorial explains how the temperature of ocean water is inversely proportional to depth below 900 meters, using the formula T = 4500 / X. It demonstrates calculating temperature differences at depths of 1200 and 2500 meters, resulting in a difference of 1.95 degrees Celsius. The tutorial also guides on identifying the correct graph that represents this inverse relationship, emphasizing graph D as the correct choice.

What is the relationship between temperature (T) and depth (X) in the ocean below 900 meters?

• T is independent of X

• T is equal to X

• T is inversely proportional to X

• T is directly proportional to X

Using the formula T = 4500 / X, what is the temperature at a depth of 1200 meters?

• 3.75 degrees Celsius

• 4.5 degrees Celsius

• 2.5 degrees Celsius

• 5.0 degrees Celsius

What is the temperature difference between depths of 1200 meters and 2500 meters?

• 1.5 degrees Celsius

• 2.5 degrees Celsius

• 2.0 degrees Celsius

• 1.95 degrees Celsius

Which graph correctly represents the inverse relationship between T and X?

• Graph B

• Graph D

• Graph A

• Graph C

If X is a very large number, what happens to the value of T?

• T becomes very large

• T becomes very small

• T equals zero

• T remains constant