In a Mathematics test, ⅕ of the students scored grade A, ⅙ of the students scored grade B and ⅕ of the remainder of students got grade C. The rest of the students either had grade D or have failed. If the number of students who failed the test was half the number of those who scored grade D, and the number of students who scored grade C is 57, what is the number of students who took the test?​

You drop a rubber ball off the roof of a 50 meter high building onto a paved parking lot. it bounces back up with every bounce, but not quite all the way back up to you. after the first bounce it bounces back only 80 percent of the distance it was dropped from. the pattern continues, meaning after every bounce it comes up to just 80 percent of the previous maximum height. so if before the first bounce the height is 50 meters, what height does the ball reach after the fifth bounce? round your answer to one decimal place and chose the correct response from the choices below:

Which value would be a solution for x in the inequality 47-4x< 7

Handsome jack is buying a pony made of diamonds. the price of the pony is p dollars, and jack also has to pay a 25% diamond pony tax. which of the following expressions could represent how much jack pays in total for the pony?