Step-by-step explanation:
-4,5is the correct answer
Answer:
Step-by-step explanation:
Assuming there is a punitive removal of one point for an incorrect response.
Five undiscernable choices: 20% chance of guessing correctly -- Expectation: 0.20*(1) + 0.80*(-1) = -0.60
Four undiscernable choices: 25% chance of guessing correctly -- Expectation: 0.25*(1) + 0.75*(-1) = -0.50
I'll use 0.33 as an approzimation for 1/3
Three undiscernable choices: 33% chance of guessing correctly -- Expectation: 0.33*(1) + 0.67*(-1) = -0.33 <== The approximation is a little ugly.
Two undiscernable choices: 50% chance of guessing correctly -- Expectation: 0.50*(1) + 0.50*(-1) = 0.00
And thus we see that only if you can remove three is guessing neutral. There is no time when guessing is advantageous.
One Correct Answer: 100% chance of guessing correctly -- Expectation: 1.00*(1) + 0.00*(-1) = 1.00
let's firstly convert the mixed fractions to improper fractions, and then get their product.
![\stackrel{mixed}{1\frac{1}{4}}\implies \cfrac{1\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{5}{4}} ~\hfill \stackrel{mixed}{2\frac{3}{4}}\implies \cfrac{2\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{11}{4}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{5}{4}\cdot \cfrac{11}{4}\implies \cfrac{(5)(11)}{(4)(4)}\implies \cfrac{55}{16}\implies 3\frac{7}{16}](https://tex.z-dn.net/?f=%5Cstackrel%7Bmixed%7D%7B1%5Cfrac%7B1%7D%7B4%7D%7D%5Cimplies%20%5Ccfrac%7B1%5Ccdot%204%2B1%7D%7B4%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B5%7D%7B4%7D%7D%20~%5Chfill%20%5Cstackrel%7Bmixed%7D%7B2%5Cfrac%7B3%7D%7B4%7D%7D%5Cimplies%20%5Ccfrac%7B2%5Ccdot%204%2B3%7D%7B4%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B11%7D%7B4%7D%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Ccfrac%7B5%7D%7B4%7D%5Ccdot%20%5Ccfrac%7B11%7D%7B4%7D%5Cimplies%20%5Ccfrac%7B%285%29%2811%29%7D%7B%284%29%284%29%7D%5Cimplies%20%5Ccfrac%7B55%7D%7B16%7D%5Cimplies%203%5Cfrac%7B7%7D%7B16%7D)