Herbert has three lawn-mowing jobs. One lawn is shaped like a trapezoid, one like a triangle, and one like a rectangle. The trapezoidal lawn has bases that are 90 feet and 126 feet and a height of 75 feet. The triangular lawn has a height of 80 feet and a base of 105 feet. The rectangular lawn has a length of 120 feet and width of 90 feet. If Herbert can cut a 160 ft × 70 ft lawn in 2 hours, how long will it take him to mow all three lawns?

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?