Question

Someone please explain!
The numbers of pages in the books in a library follow a normal distribution. If the mean number of pages is 180 and the standard deviation is 30 pages, what can you conclude?
What percentage of books have fewer or more pages than 150.

Answer 1

I must be figuring this out wrong because I figured it was 68% with pages between 150 and 210.
but my choices are different

60% fewer than 150 pages
16% fewer than 150 pages
95 % have more than 150 pages (this one is probably the right answer but how?)
16% have more than 150 pages

Answer 2

***I must be figuring this out wrong because I figured it was 68% with pages between 150 and 210. ***
that is correct.
but they want the percent of books with *less than 150 pages*

Answer 3

in other words, if we draw the bell curve:


the percent area on the *outside* of 150 to 210 is 32%
because the total area must add up to 100% and 100-68= 32

the areas of the "left tail" and "right tail" are equal and add up to 32
that means each is 16%