Which of these situations could be written as an equation with one variable?

A
Penny picked 35 apples, Ben picked 22 and Sam picked 17. They picked 74 apples all together. Who picked the most apples?

B
Harriet and Lea found 9 four-leaf clovers on the baseball field in all. Harriet found 5 of them. How many clovers did Leah find?

C
There were 45 doughnuts at the snack table today. Tanisha brought 33 of them, and Doug brought 12. Where did Tanisha buy her doughnuts?

D
Lori bought the most T-shirts of anyone in her family. She bought 1 more T-shirt than Thea and 3 more than Pino. How many shirts did Lori buy?

BACK

Amachine that produces a special type of transistor (a component of computers) has a 2% defective rate. the production is considered a random process where each transistor is independent of the others. (a) what is the probability that the 10th transistor produced is the first with a defect? (b) what is the probability that the machine produces no defective transistors in a batch of 100? (c) on average, how many transistors would you expect to be produced before the first with a defect? what is the standard deviation? (d) another machine that also produces transistors has a 5% defective rate where each transistor is produced independent of the others. on average how many transistors would you expect to be produced with this machine before the first with a defect? what is the standard deviation? (e) based on your answers to parts (c) and (d), how does increasing the probability of an event a↵ect the mean and standard deviation of the wait time until success?