On a certain standardized test used for college entrance purposes, the mean score was 21 and the standard deviation was 5. The distribution was approximately normal. Carlos scored 31, two standard deviations above the mean. A total of 1.5 million people across the country took the test at the same time as Carlos. How many people had scores lower than Carlos?

a. 1,465,500 people
b. 977,000 people
c. 204,000 people

A

Step-by-step explanation:

Carlos' score was 2 standard deviations from the mean, so his z-score was 2.0. You can either use the empirical 68-95-98.5 rule, or you can plug it into your calculator as normalcdf(-999, 2) = .977

So 97.7% of people had a score lower than Carlos!

.977 * 1.5 million = 1,465,500 people

add an image !

step-by-step explanation:

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl