Interesting GMATFix Problem-36

[arora007]

The test scores of 1050 students have a normal distribution. If the average test score is 73 and the standard deviation is 10.5, approximately how many students have a test score less than 62.5?
A)147
B)168
C)205
D)288
E)357

[sanabk]

From the attached image, one can say that 68% of the class received a score within 1 standard deviation of the mean (73). This leaves 32% of which 16% are below 1SD of mean (62.5) and 16% are above 1SD of mean (83.5).

The number of students with score less than 62.5 = 16%(1050)=168.
B

[arora007]

From the attached image, one can say that 68% of the class received a score within 1 standard deviation of the mean (73). This leaves 32% of which 16% are below 1SD of mean (62.5) and 16% are above 1SD of mean (83.5).

The number of students with score less than 62.5 = 16%(1050)=168.
B

Do we need to learn what u have given in this figure, 68%, 16% etc. ?

[sanju09]

From the attached image, one can say that 68% of the class received a score within 1 standard deviation of the mean (73). This leaves 32% of which 16% are below 1SD of mean (62.5) and 16% are above 1SD of mean (83.5).

The number of students with score less than 62.5 = 16%(1050)=168.
B

Do we need to learn what u have given in this figure, 68%, 16% etc. ?

Well, it's helpful if we really do, but the demonstration here is a treat to watch.