Math GRE pratice 2

count the dot below the fitted line that are greater than 20hours

3/10

Set X={a, b, c}, where a < b < c. If the average (arithmetic mean) of a and b is 3x - 13, and the average of b and c is 3x + 11, what is the range of set X?

Find c-a:

which months have 31 days

Jan, Mar,May, July, August, October, Dec

When positive integer k is divided by 5, the remainder is 2. When k is divided by 6, the remainder is 5. If k is less than 40, what is the remainder when k is divided by 7?

List all value of k by using the first rule

a, b and c are positive integers. If b equals the square root of a, and if c equals the sum of a and b, which of the following could be the value of c? Indicate all such values.

The product of odd and even is always even #-> c must be a even number-> we can eliminate the odd value c=b(b+1) c is the product of two consecutive number

In how many of the columns is the number of students with a score in that category from the Celeraville Academy greater than the number of students with a score in that category from the Newboard Free School?

compare each column of New board school corresponding to the column Celeraville school. 4

combination

n choose r

What is the average (arithmetic mean) of all multiples of 10 from 10 to 400 inclusive

or another fast way to solve 10+400/2=205