Number Stuff
The sum of three distinct primes is 40. What are the three primes?
31, 7 , 2
Let x be a number between -3.8 and 1.7 such that the distance between x and −3.8 on a number line is exactly two times the distance between x and 1.7. What is the value of x? Express your answer as a decimal to the nearest tenth.
-0.1
What is the degree measure of the acute angle formed by the hour and minute hands at 2:30?
165 degrees
A math textbook is on sale for $45. If this cost represents a 40% discount, what was the original cost of the textbook?
$75
According to "Boys Bathroom Etiquette", it is rude to stand directly next to someone while peeing. If two people randomly choose two stalls into a row of five stalls, then what is the probability that they will violate bathroom etiquette? Express your answer as a common fraction.
Using only the eight digits 3, 4, 7, 8 I create two two-digit numbers whose product is as large as possible. What is the sum of those two numbers?
157
What is the inverse of the function y=2x-1?
y= x/2+0.5
If the sum of the measures of the interior angles of a polygon is 5040 degrees, how many sides does the polygon have?
30
Ramon built a rectangular pen for his dog with dimensions 10 feet by x feet. Heidi builds a circular pen of radius 5 feet for her dog. If the two pens have the same area, what is the value of x? Express your answer as a decimal to the nearest tenth.
7.9
How many distinct pairs of parallel edges are there in a cube?
18
What is the sum of the base-ten numbers from 5 to 50, inclusive, that are palindromes when written in base two?
210
If x + 1/x = 3, and x - 1/x = 2 then what is the value of x4-1/x4?
42
Points A, B, C and D have coordinates A(5, 7), B(7, 1), C(17, m) and D(−1, 3). If line segments AB and CD are perpendicular, what is the value of m?
9
A positive number n is 25% of 6/5 of its square. What is the value of n? Express your answer as a decimal to the nearest tenth.
3.3
One of the dots on a standard 6-sided die is removed randomly. The die is then rolled and the result is the number of dots on the top face. What is the expected value of the roll?
10/3