Answer:42%
Step-by-step explanation:
Answer:
a. average speed is 12km/hr
b. $5.50 dollars per hour
c. $0.46 per km
Step-by-step explanation:
a. 48km/4hrs = 12km/hr
b. $22/4hrs = $5.50/hr
c. $22/48km = $0.45833/km rounded to $0.46/km
Matt needs to travel 3 hours.
If 40km=1 hour
400km=? But there are two distances
200/40*1=5 hours
Therefore Kali needs to travel 5 hours to be 200 km away from the house.
If 50km=1 hour
200km=?
200/50*1hr=4hrs Therefore Matt needs to travel 4hrs to be 200 km away from the house. But Kali traveled 1hr earlier than Matt. 4hrs-1hr=3hrs
Therefore Matt has to travel for 3 hours to be 400km away from Kali.
(a) 0.059582148 probability of exactly 3 defective out of 20
(b) 0.98598125 probability that at least 5 need to be tested to find 2 defective.
(a) For exactly 3 defective computers, we need to find the calculate the probability of 3 defective computers with 17 good computers, and then multiply by the number of ways we could arrange those computers. So
0.05^3 * (1 - 0.05)^(20-3) * 20! / (3!(20-3)!)
= 0.05^3 * 0.95^17 * 20! / (3!17!)
= 0.05^3 * 0.95^17 * 20*19*18*17! / (3!17!)
= 0.05^3 * 0.95^17 * 20*19*18 / (1*2*3)
= 0.05^3 * 0.95^17 * 20*19*(2*3*3) / (2*3)
= 0.05^3 * 0.95^17 * 20*19*3
= 0.000125* 0.418120335 * 1140
= 0.059582148
(b) For this problem, let's recast the problem into "What's the probability of having only 0 or 1 defective computers out of 4?" After all, if at most 1 defective computers have been found, then a fifth computer would need to be tested in order to attempt to find another defective computer. So the probability of getting 0 defective computers out of 4 is (1-0.05)^4 = 0.95^4 = 0.81450625.
The probability of getting exactly 1 defective computer out of 4 is 0.05*(1-0.05)^3*4!/(1!(4-1)!)
= 0.05*0.95^3*24/(1!3!)
= 0.05*0.857375*24/6
= 0.171475
So the probability of getting only 0 or 1 defective computers out of the 1st 4 is 0.81450625 + 0.171475 = 0.98598125 which is also the probability that at least 5 computers need to be tested.
