Video: GCSE Mathematics Foundation Tier Pack 3 • Paper 1 • Question 9

GCSE Mathematics Foundation Tier Pack 3 • Paper 1 • Question 9

01:24

Video Transcript

A sweet packet contains seven red and nine blue sweets. James randomly takes a sweet from the bag. Work out the probability that the sweet is blue.

So the first step is to actually work out what are the total number of sweets in our packet. Now to calculate this, what we’re gonna do is we’re gonna add seven and nine. That’s because we’ve got seven red and nine blue sweets in the bag. So this is gonna be equal to 16. So we can say that the total number of sweets in the bag is 16.

But we’ve worked out the total number of sweets. And why is this useful? Well, this is useful because what we need to do is work out the probability that the sweet is blue. And to find the probability that the sweet is blue, we can use this equation. And this equation states that the probability that the sweet is blue, so 𝑃 blue, is equal to the number of blue sweets in the bag divided by the total number of sweets in the bag.

So therefore using this, if we’re trying to work out the probability of there being a blue sweet selected, we’re gonna have nine, because there are nine blue sweets, over 16. And that’s because the total number of sweets was 16. So therefore, we can say that if a sweet packet contains seven red and nine blue sweets and James randomly takes a sweet from the bag, the probability that the sweet is blue is nine over 16 or nine sixteenths.

Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.