If the two spinners below are spun,what is the probability that the numbers will add to less than 6

Question

First spinner has 3 sections

Second spinner has 4 sections

Help! I have no clue what to do the answers are all in fractions and I don't know why

Answer 1

Hi Monica

 

It looks like we're missing some information here. The answer will be a fraction because probability is a number between 0 and 1. A probability of 0 means an event is impossible, and a probability of 1 means an event is certain. Anything between impossible and certain has a probability between 0 and 1, which can be written as a fraction (in your case), or a percent.

 

There are two important pieces of information that are missing from what I'm assuming is a diagram or visual. First, which numbers are written in the sections of the spinners? You said the first has 3 sections and the other has 4, but what numbers are written? Is it just 1,2,3 and 1,2,3,4? Second, are all the sections of the spinners equal in size?

 

I'm going to assume something so that I can help you answer. I'm going to assume that the first spinner has the numbers 1, 2, and 3 and all three sections are equal in size. That means the probability of getting a 1 is 1/3, the probabilty of getting a 2 is also 1/3, and the probability of getting a 3 is also 3/3. They're all equally likely. I'm also going to assume that the second spinners has the number 1, 2, 3, and 4 and all four sections are equal in size.

 

I want to find the probability that the two numbers I land on sum to less than six. Is that even possible? Well sure, if I get a 1 on the first spinner, than any number from the second spinner will sum to less than six (1+1, 1+2, 1+3, and 1+4 are all less than six). If I get a 2 on the first spinner, than I have to spin a 1, 2, or 3 on the second spinner. If I get a 3 on the first spinner, then I must get a 1 or 2 on the second spinner.

 

That means that if I count them all up, there are 9 possible ways to spin numbers that add to less than 6. How many numbers are there total? Well if there's 3 sections in the first and 4 in the second, that means there are 12 combinations total. 9 out of the 12 possibilities have sums less than six, so the probability of the sum being less than six is 9/12, which reduces to 3/4.

 

Questions?