Rex is currently taking physics as one of his electives in school. His grade at the end of the year is determined by the average of four exams, each worth 100 points. On his first test he got an 84, on his second he got a 86, and on his third an 92. What must he score on his fourth exam to get an A (90%) in the course? a. 98 b. 90 c. 88 d. 86

The class wants to raise a total of $750.if they receive a profit of $1.25 from each candybar sold, how many bars must they sell to reachtheir goal

Which of the symbols correctly relates the two numbers below check all that apply 6? 6

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.