GCSE Secondary Maths Age 13-17 - Probability & Statistics: Probability Basics - Explained

The video tutorial explains how to calculate probabilities for different colored counters in a bag. It starts by introducing the problem and the given probabilities for blue and yellow counters. The tutorial then calculates the probabilities for red and white counters, using the information that the probability of red is twice that of white. It determines the total number of counters in the bag and calculates the number of red counters. Finally, it explains why there must be an even number of marbles in a box when the probability of selecting a silver marble is 0.5.

What is the probability of drawing a blue counter from the bag?

• 0.30

• 0.50

• 0.45

• 0.25

If the probability of drawing a red counter is twice that of a white counter, what is the probability of drawing a white counter?

• 0.20

• 0.25

• 0.15

• 0.10

How many total counters are there in the bag?

• 30

• 45

• 35

• 40

How many red counters are in the bag?

• 6

• 9

• 7

• 8

If there are 40 counters in total, what is the probability of drawing a yellow counter?

• 0.15

• 0.20

• 0.25

• 0.30

Why must there be an even number of marbles in the box if the probability of picking a silver marble is 0.5?

• Because half of an odd number is a whole number

• Because half of an even number is a whole number

• Because 0.5 is an odd number

• Because 0.5 is an even number

What fraction represents the probability of drawing a silver marble?

• 1/4

• 1/2

• 1/3

• 1/5