Nick is doing some math exercises on a website called Khon Academy. In Khon Academy, you have to get at least 70%, percent of the problems in an exercise right in order to gain proficiency.
So far, Nick answered one question, and he didn't get it right. Suppose he answers 75%, percent of the following questions correctly and gains proficiency in the exercise.
Write an inequality in terms of that models the situation.

Here is their argument. given the obtuse angle x, we make a quadrilateral abcd with ∠dab = x, and ∠abc = 90◦, and ad = bc. say the perpendicular bisector to dc meets the perpendicular bisector to ab at p. then pa = pb and pc = pd. so the triangles pad and pbc have equal sides and are congruent. thus ∠pad = ∠pbc. but pab is isosceles, hence ∠pab = ∠pba. subtracting, gives x = ∠pad−∠pab = ∠pbc −∠pba = 90◦. this is a preposterous conclusion – just where is the mistake in the "proof" and why does the argument break down there?

Astandard deck of cards contains 52 cards. one card is selected from the deck. (a) compute the probability of randomly selecting a seven or king. (b) compute the probability of randomly selecting a seven or king or jack. (c) compute the probability of randomly selecting a queen or spade.

Adam used 1072.4 gallons of water over the course of 7 days. how much water did adam use, on average, each day?