There is a bag filled with 5 blue, 2 red and 3 green marbles,

A marble is taken at random from the bag, the colour is noted and then it is replaced.

Another marble is taken at random

What is the probability of getting 2 different colours?

0.62

Step-by-step explanation:

There are a total of 10 marbles in the bag.

P (blue and not blue) = 5/10 * 5/10 = 25/100

P (red and not red) = 2/10 * 8/10 = 16/100

P (green and not green) = 3/10 * 7/10 = 21/100

P = 25/100 + 16/100 + 21/100

P = 62/100

P = 0.62

Alternatively, you can calculate it this way:

P (both blue) = (5/10) ² = 25/100

P (both red) = (2/10) ² = 4/100

P (both green) = (3/10) ² = 9/100

P = 1 - (25/100 + 4/10 + 9/100)

P = 1 - 38/100

P = 62/100

P = 0.62