Answer:
C) 8 and 9
Step-by-step explanation:
We know that 70 is between two perfect squares.
The square numbers 64 and 81 can help us solve this question.
64<70<81
We take square root to get:

We simplify this to get:

Therefore √70 is between 8 and 9.
The correct option is C.
Answer:
61,239,550
Step-by-step explanation:
We let the random variable X denote the IQ scores. This would imply that X is normal with a mean of 100 and standard deviation of 17. We proceed to determine the probability that an individual chosen at random from the population would be a genius, that is;
Pr( X>140)
The next step is to evaluate the z-score associated with the IQ score of 140 by standardizing the random variable X;

The area to the right of 2.3529 will be the required probability. This area from the standard normal tables is 0.009314
From a population of 6,575,000,000 the number of geniuses would be;
6,575,000,000*0.009314 = 61,239,550
Answer: -1/2 or -0.5.
Explanation: -2- -1, -6- -2= -0.5