Calculate probabilities of dependent events

Maths

Amy is going to pick 2 biscuits from a box. Some are chocolate and some are plain. The probability tree shows the probability information.

James is also going to pick 2 biscuits from a box. Some are chocolate and some are plain. The probability tree shows the probability information.

Here is a probability tree showing Amir taking red and blue sweets from a bag.

Probability of a dependent event is also called?

The fractions on each branch do not sum to 1.

The second part of the probability tree has incorrect probabilities.

Simon has drawn this probability tree for a question on dependent probability. What mistake has he made?

This tree diagram shows Amir taking red and blue sweets from a bag. He does not replace the sweet after he has taken one.