Simple Probability

This lesson can be used for revision for the higher Maths GCSE. The examples are quick and concise with exam style questions, go to GCSE Maths if you need more in-depth explanations.

How to answer simple Probability questions
Example 1: The probability of a seed flowering is 0.2. Estimate how many seeds will flower if I plant 200 seeds.

Example 2: The probability of a biased coin landing on heads is 0.3. Estimate how many heads you would expect if I tossed the coin 400 times.

Example 3: The probability of a biased coin landing on heads is 0.2. Estimate how many tails you would expect if I tossed the coin 300 times.

Example 4: A tennis player wins with probability 0.2 and draws with probability 0.15. If she plays 200 times, estimate the number of loses she suffers.

Example 5: Jack sows 300 sunflower seeds. The probability of a seed flowering is 0.7. Work out an estimate for the number of these seeds that will flower.

Example 6: The probability that a biased dice will land on a five is 0.3. Megan is going to roll the dice 400 times. Work out an for the number of times the dice will land on a five.

Example 7: Rhiana plays a game. The probability that she will lose the game is 0.32. The probability that she will draw the game is 0.05. Rhiana is going to play the game 200 times. Work out an estimate for the number of times Rhiana will win the game.

Example 8: Jane has a packet of seeds. The probability that a seed will grow is 0.75
a) What is the probability that a seed will not grow?
Jane plants 200 of these seeds.
b) Estimate the number of seeds that will grow. Go to next lesson