Answer:
times the height, width and base
Step-by-step explanation:
The first question the answer to it is 30.
To do that divide 50/2 and see how many movies she can buy, which 25, then add the 5 free movies which gives you 30.
And the second part of the question I think is missing a picture or something.
Answer:
4.924 years
Step-by-step explanation:
Lets denote X the lifetime of a tv tube (In years). X has distribution
, with
unknown.
We know that P(X < 4) = 0.2. Using this data, we can find the value of
throught standarization.
Lets call
the standarization of X. Z has distribution N(0,1), and its cummulative function,
is tabulated. The values of
can be found in the attached file.

The value q such that
doesnt appear on the table. We can find it by using the symmetry of the normal density function. The opposite of q, -q must verify that
, hence -q must be equal to 0.84. Thus, q = -0.84
But this value of q should match with the number
, so we have



Thus, the expected lifetime of TV tubes is 4.924 years.
I hope this works for you!
The answer is 80 because 80 divided by 10 = 8