Word Problem

[crosscountryrunner]

Jay has a business mowing lawns for the people in his neighborhood. He charges $13 for his basic lawn job. One neighbor offers to make him a deal: He will put two $10 bills and eight $5 bills in a bag and let Jay draw out two bills. Is it in Jay’s favor to accecpt? Why?

I know that the answer is it is in Jay's best intrest to not accecpt, because there is a bigger chance of him receving only $10 but I am unsure how I would write my explanation out for this. Could someone help me please.

 

[Deleted member 4993]

Jay has a business mowing lawns for the people in his neighborhood. He charges $13 for his basic lawn job. One neighbor offers to make him a deal: He will put two $10 bills and eight $5 bills in a bag and let Jay draw out two bills. Is it in Jay’s favor to accecpt? Why?

I know that the answer is it is in Jay's best intrest to not accecpt, because there is a bigger chance of him receving only $10 but I am unsure how I would write my explanation out for this. Could someone help me please.

This is a problem of "expected value".

What are the events:

(1) The first bill drawn is 10 and the second bill is 10 - the chance of that is 2/10*1/9 = 2/90

(2) The first bill drawn is 10 and the second bill is 5 - the chance of that is 2/10*8/9 = 16/90

(3) The first bill drawn is 5 and the second bill is 10 - the chance of that is 8/10*2/9 = 16/90

(4) The first bill drawn is 5 and the second bill is 5 - the chance of that is 8/10*7/9 = 56/90

Now find the expected pay out.....