Answer:
P=0.147
Step-by-step explanation:
As we know 80% of the trucks have good brakes. That means that probability the 1 randomly selected truck has good brakes is P(good brakes)=0.8 . So the probability that 1 randomly selected truck has bad brakes Q(bad brakes)=1-0.8-0.2
We have to find the probability, that at least 9 trucks from 16 have good brakes, however fewer than 12 trucks from 16 have good brakes. That actually means the the number of trucks with good brakes has to be 9, 10 or 11 trucks from 16.
We have to find the probability of each event (9, 10 or 11 trucks from 16 will pass the inspection) . To find the required probability 3 mentioned probabilitie have to be summarized.
So P(9/16 )= C16 9 * P(good brakes)^9*Q(bad brakes)^7
P(9/16 )= 16!/9!/7!*0.8^9*0.2^7= 11*13*5*16*0.8^9*0.2^7=approx 0.02
P(10/16)=16!/10!/6!*0.8^10*0.2^6=11*13*7*0.8^10*0.2^6=approx 0.007
P(11/16)=16!/11!/5!*0.8^11*0.2^5=13*21*16*0.8^11*0.2^5=approx 0.12
P(9≤x<12)=P(9/16)+P(10/16)+P(11/16)=0.02+0.007+0.12=0.147
The second one is correct
Answer:
36 ft by 16 ft
Step-by-step explanation:
To solve this problem, you need to find dimensions of a rectangle such that the perimeter is 104 ft and the area is 576 ft. The perimeter is twice the sum of length and width, so the sum of length and width is 52 ft.
The area is the product of length and width, so if w represents the width, we have ...
w(52 -w) = 576
w² -52w = -576 . . . . . eliminate parentheses, multiply by -1
w² -52w +26² = 26² -576 . . . . . . complete the square
(w -26)² = 676 -576 = 100
w = 26 ±√100 = {16, 36}
If the width is the short dimension, it is 16 feet. Then the length is 36 feet.
