The mean of 50 test scores was calculated as 86. But, it turned out that one of the scores was misread as 91 but it was 66. What is the correct mean of the test scores?
A. 84
B. 85
C. 85.5
D. 86.5

Which expressions are equivalent to the one below? check all that apply. 25x/5x a. 5x b. 5 c. 5x•5x/5x d. 25x e. (25/5)^x f. (25-5)^x

My math teacher told my class to "steal" a 6th grade fraction word problem from the internet, word problems? : -p requirements: only a 1 step word problem. needs to be complex.

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.