Question

Which is a counterexample that disproves the conjecture?

For all real numbers n, 2^n ≥ 1.

A. n = 0
B. n = 0.5
C. n = –1
D. n = 3

Answer 1

With A you get 1
With B you get 2^(0.5) which is more than 1
With C you get 2^-1 = 1/2 ---> ANSWER
With D you get 8

Answer 2

Ah, I see. Thanks!

Answer 3

You welcome :)

Answer 4

How about this one?

Choose the counterexample that disproves the conjecture.

If n is a two-digit prime number, then the two digits must be different.

A. n = 22
B. n = 17
C. n = 11
D. n = 10

Explanation as well?

Answer 5

n, _ _

A, has the same digits but not prime, because 22 has also factors such as 2 and 11.
B is prime, but not same digits.
C same digits and prime . (YOUR ANSWER)
D not same digits, and not prime.

Answer 6

Not C.

Answer 7

I misread the question.

Answer 8

Ya, its not C

Answer 9

B, because it's the only number with 2 different digits that's prime.

Answer 10

Thought so! Thanks again :)

Answer 11

np