The mean of the test is 143 and the standard deviation is 15.7. if the scores have a bell-shaped distribution, what percentage of the scores are between 111.6 and 174.4?

If you're allowed to use a calculator here, use it!

This is basic normal probability, with mean 143 and s. d. 15.7.

I typed in the following:

normal cdf(111.6, 174.4, 143, 15.7) and got the probability 0.954.  In words, more than 95% of scores were between 111.6 and 174.4 on this test.

Ithink it is correct but just ask someone else but i am sure it it