GCSE Secondary Maths Age 13-17 - Ratio, Proportion & Rates of Change: Ratios 2 - Explained

The video tutorial explains how to solve a probability problem involving counters in a bag. It starts by introducing the problem, which involves calculating the probability of selecting a red counter given the ratios of red to blue counters and the probability of selecting a purple counter. The tutorial walks through setting up the problem, calculating the necessary probabilities, and solving for the probability of selecting a red counter. It concludes with advice on practicing similar ratio problems.

What is the ratio of red counters to blue counters in the bag?

• 5 to 1

• 1 to 5

• 17 to 3

• 3 to 17

If the probability of picking a purple counter is 0.2, what is the combined probability of picking a red or blue counter?

• 1.0

• 0.5

• 0.2

• 0.8

How many total parts are there in the bag according to the given probabilities?

• 35

• 30

• 25

• 20

What is the probability of picking a red counter from the bag?

• 3/25

• 2/25

• 4/25

• 1/25

How many marks were allocated for finding the probability of picking a red counter?

• 1 mark

• 2 marks

• 3 marks

• 4 marks