Thread: Help with probability,compound interest

Hello does anyone understand how to work out these questions? Please help.

Q1. Two boxes contain coloured bricks.
Box A contains 2 red bricks, 3 blue bricks and 1 yellow brick.
Box B contains 3 red bricks, 2 yellow bricks and 1 green brick.
Janet selects one brick from box A and one brick from box B.
Calculate the probability that the two bricks will be of the same colour.

Q2. A painting was valued at £600 on 1 January 2004.
The value of the painting is predicted to increase at a rate of R% per annum.
The predicted value, £V, of the painting after n years is given by the formula
V = 600 × (1.055)^n
Use your calculator to find the predicted value of the painting after 15 years.

Q1. So the only combinations that have the same colour are:
Red and Red, Yellow and Yellow (since blue and green only appear in one of the boxes)

red in box A = 2/6
red in box B = 3/6
probability of getting this is 2/6 x 3/6 = 6/36

yellow in box A = 1/6
yellow in box B = 2/6
probability of getting this is 1/6 x 2/6 = 2/36

Add these probabilities together:
6/36 + 2/36 = 8/36 = 4/18 = 2/9
and there's your answer!

Q2. You have already been given the answer! It's just simple substitution. If
V = 600 × (1.055)^n
where n is the number of years and they are asking for its value in 15 years...
C'mon you can do this