Justin’s teacher places a ticket with a student’s name in a jar each time they perform an act of kindness. At the end of the week the teacher will draw a ticket from the jar and award a prize. Justin has 13 tickets so far, with a total of 100 in the whole jar. His goal is to have 20 tickets, and he’s estimating the total number of tickets at that point would be about 200. What is the probability of him winning the drawing if he meets his goal?(
If Justin has 20 tickets and there are a total of 200 tickets in the jar, then the probability of him winning the drawing would be 20/200, which simplifies to 1/10 or 0.1. Therefore, Justin would have a 10% chance of winning the drawing if he meets his goal of 20 tickets.
A desk drawer has 20 pens: 4 fountain pens, 10 gel pens, and 6 ballpoint pens. What is the probability of randomly choosing a gel pen, replacing it, and then choosing a fountain pen?
To find the probability of both events happening (choosing a gel pen and then a fountain pen), we multiply the probabilities of each event.
The probability of choosing a gel pen on the first draw is 10/20 = 1/2.
Since the pen is replaced after the first draw, the probability of choosing a fountain pen on the second draw is 4/20 = 1/5.
Therefore, the probability of randomly choosing a gel pen and then a fountain pen is:
(1/2) * (1/5) = 1/10 or 0.1
So, the probability of randomly choosing a gel pen, replacing it, and then choosing a fountain pen is 0.1 or 10%.