If 3 cats can kill 3 rats in 3 minutes, how long will it take 100 cats to kill 100 rats?

X+y=-4 x-y=2 use elimination with adding and subtraction

If 1.4% of the mass of a human body is calcium, how many kilograms of calcium are there in a 165-pound man? 1.0 kg ca 5.1 kg ca 1.0 x 102 kg ca 5.1 x 102 kg ca

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?