Data Sufficiency

was 70 the average grade on a class test?
1. on the test,half of the class had grades below 70 and half of the class had grades above 70.
2. the lowest grade on the test was 45 and the highest grade on the test was 95.

pradeepkaushal9518 wrote:was 70 the average grade on a class test?
1. on the test,half of the class had grades below 70 and half of the class had grades above 70.
2. the lowest grade on the test was 45 and the highest grade on the test was 95.

to find average you need sum and number of student

satement 1)half had grade below 70 and half had above 70 so average can be 70
statement 2)the lowest grade on the test was 45 and the highest grade on the test was 95
no information added
so 2 is out of question
so i would say only staement 1 is sufficient

was 70 the average grade on a class test?
1. on the test,half of the class had grades below 70 and half of the class had grades above 70.
2. the lowest grade on the test was 45 and the highest grade on the test was 95.

You can find out pretty quickly that the answer to this question is E.

St. (1) Examples:

15, 15, 75, 75 ... These scores fit the conditions of (1), and the average is 45.

69, 69, 71, 71 ... These scores fit the conditions of (1), and the average is 70.

INSUFFICIENT

St. (2) Examples:

45, 95 ... These scores fit the conditions of (2), and the average is 70.

45, 45, 95 ... These scores fit the conditions of (2), and the average is less than 70.

INSUFFICIENT

St. (1) and (2) together:

45, 45, 95, 95 ... These scores fit the conditions of (1) and (2), and the average is 70.

45, 46, 95, 95 ... These scores fit the conditions of (1) and (2), and the average is greater than 70.

INSUFFICIENT

ok thanks raz for yr response. initially i have choosen A. which was wrong