Question

The probability of a certain brand of battery going dead within 15 hours is 1/3. Noah has a toy that requires 4 of these batteries. He wants to simulate the situation to estimate the probability that at least one battery will die before 15 hours are up. 1. Noah will simulate the situation by putting marbles in a bag. Drawing one marble from the bag will represent the outcome of one of the batteries in the toy after 15 hours. Red marbles represent a battery that dies before 15 hours are up, and green marbles represent a battery that lasts longer. How many marbles of each color should he put in the bag? Explain your reasoning. *

Answer 1

a.

Noah put marbles on a bag, each color marble represents that the battery of the toy died before 15 hours (red marbles) or that the battery lasted after 15 hours (green marbles)

There are 4 batteries on the toy, for each battery there are two possible outcomes, each one represented by a red and green marble.

So, for each battery, he has to put two marbles. There will be 4 red marbles and 4 green marbles in the bag.

b.

To estimate the probability that at least one battery will die within 15 hours, you have to calculate the expected value.