Question

A bag contains 40 marble ,4 of which are blue , 10 are red ,25 are green , and 1 purple Shawna takes a marble out of the bag, records the color and returns it to the bag . How many green marbles should she exepect after 400 trials

Answer 1

She should expect 250 green marbles.

She has a 25 out of 40 chance of selecting a green marble each time since she is putting it back in the bag each time. 25/40 reduces to 5/8. Multiply 5/8 by 400 and you get 2000/8. Reduce the fraction to 250/1 or 250.