A test has 20 true/false questions. How many different tests can be turned into

[Jay]

the teacher? How would i figure this out?

 

[[= a♥m♥y =]]

2*20 = 40
Because there are two possible answers for each question.

 

[Krazy K]

let's see:

T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T 20 true
T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-F
T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-F-T
T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-F-T-T
T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-F-T-T-T
T-T-T-T-T-T-T-T-T-T-T-T-T-T-T-F-T-T-T-T
T-T-T-T-T-T-T-T-T-T-T-T-T-T-F-T-T-T-T-T
T-T-T-T-T-T-T-T-T-T-T-T-T-F-T-T-T-T-T-T

....KEEP DOING THIS UNITL YOU GET TO ALL FALSE

F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F-F 20 false


An easiar way to do this is 2(20!)
=2x20x19x18x17x16x15x14x13x12x11x10x9x8x7x6x5x4x3x2x1=
my calculator won't go that high sorry

 

[Voltron]

wouldn't it be 2^20? Because each answer can either be true or false, meaning there are two options, and since they are independent of each other wouldn't you multiply them all together? I could be insanely wrong, it's been a while since I took algebra 2. Try using your calculator 2nCr20 and see what comes up.

 

[Bwahaha]

i dont know i just need 2 points

 

[bohrmetodeath]

None! You can't make a test become a teacher!

Terrible, I know...

Anway, each question has two possible answers, so, every time you add a question, you double the number of possible outcomes. One question has two possibilities. Two questions have four possibilities. Three questions have eight possibilities... and so on.

So, with 20 questions, you have 2^20 different possibilities, which turns out to be 1,048,576.