## Question 4

Question 4 A box holds 5 blue beads and 2 red beads. One bead is taken and not replaced. 4 more blue beads are then added to the box and a second bead is taken.

(a) Draw a fully labelled tree diagram.

(b) Find the probability that both beads are of the same colour.

## Question 5

A circle has centre (a,b) and passes through the point (0,3b).

Find the equation of the circle. Give your answer in the form x2 + y2 + px +qy + r = 0 where p,q and r are in terms of a or b.

## Answer

A box holds 5 blue beads and 2 red beads

Total = 7 beads

Again one bead is taken and add more 4 blue bead and again another bead is taken

a}

Consider the Tree diagram

b}

Since we have to calculate both beads are of same colour.

So, they will be (Blue and Blue}

or (Red and Red}

- Explanationfor step 2

We here use the multiplication theorem to find the required probabilities.