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

The video tutorial explains how to calculate the number of red counters in a bag given the probabilities of selecting different colored counters. It covers the calculation of probabilities for red and white counters, determining the total number of counters, and finding the number of red counters. Additionally, 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 picking a blue counter from the bag?

• 0.50

• 0.30

• 0.45

• 0.25

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

• 0.25

• 0.20

• 0.15

• 0.10

How many total counters are there in the bag?

• 40

• 35

• 30

• 45

How many red counters are in the bag?

• 9

• 8

• 7

• 6

What is the key probability value needed to solve the problem of red and white counters?

• 0.3

• 0.4

• 0.5

• 0.6

Why must there be an even number of marbles in the box?

• Because odd numbers are not allowed

• Because the box can only hold even numbers

• Because marbles are always even

• Because half of an odd number is a fraction

What fraction represents the probability of picking a silver marble?

• 1/3

• 1/4

• 1/2

• 1/5