There are 78 students from a local high school attending a concert. the concert hall has 40 rows of seats. the first row has 50 seats, and each row after that has 4 more seats than the one before. if all 78 students sit in one row and are as close to the front row as possible, in which row did the students sit? a) row 7 b) row 8 c) row 11 d) row 12

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.