This is a classic question on Speed, time, & distance.
1. When time traveled in each segment is constant, then average speed is simple mean of speeds.
2. When distance traveled in each segment is constant, then average speed is reciprocal of simple mean of reciprocal of speeds. It is basically called Harmonic mean.
So this question falls in the category of 2.
=> So, average speed = Reciprocal of mean of reciprocals of 40 & 50.
=> Average speed = Reciprocal of mean of 1/40 & 1/50.
<span>=> Average speed = Reciprocal of (1/40 + 1/50)/2 = Reciprocal of (5+4)/400 = 44 4/9 .
Hope this helps</span>
Answer:
3 (9-x- 2y) hope this helps :)
Answer:
(2, -3)
Step-by-step explanation:
i took the k-12 test and i used the answer above and got it wrong.
<span>0.002
For 6 systems with exactly 3 failures, you need to calculate 6 pick 3 or 6!/(3!3!) = 720/(6*6)=720/36=20 different combinations of 3 systems to fail. Now the probability of each of those failures will be the probability of the subsystems not failing times the probability of the subsystems fail. So 0.95^3 * 0.05^3 for 3 subsystem not failing time 3 subsystems failing. So 0.95^3 * 0.05^3 = 0.857375*0.000125 = 0.000107172. And multiply by the 6 pick 3 calculated earlier, gives.
0.000107172 * 20 = 0.002143438
And rounding to the nearest thousandth, gives 0.002</span>
Switching to common denominators, alexa ran 18/24 of a mile. caleb ran 15/24 of a mile. for alexa’s distance, you would do (2•8)+(3•8). for caleb’s distance you would do (5•3)+(8•3). hope this helped!
