Noel's club wants to purchase 8 chairs for their meeting room. the original cost for each chair was $18.99. the chairs are now on sale for 10% off. how much will noel's club save if they buy the 8 chairs on sale?
which answer gives the correct solution and explains how to check if the answer is reasonable?
a.
solution: $80
explanation: if the club paid full price for the 8 chairs, they would pay about $20 for each chair. since the chairs were 10% off, the club would pay $10 for each chair ($20 - $10).
that means they would save about 8 × $10 or $80.
b.
solution: $15.20
explanation: if the club paid full price for the 8 chairs, they would pay about $160 (8 × $20). since the chairs were 10% off, that means the club would save about 0.10 × $160 or about $16.
c.
solution: $71.92
since the original price for each chair was about $19, the club would save about $9 per chair ($19 – $10). for all 8 chairs the club would save 8 × $9 or $72.

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?