Answer:
(a) 0.06154
(b) 0.2389
(c) 0.6052
(d) 2478
Step-by-step explanation:
probability density function of the time to failure of an electronic component in a copier (in hours) is
P(x) = 1/1076e^−x/1076
λ = 1/1076
A) A component lasts more than 3000 hours before failure:
P(x>3000) = 1 − e^−3000/1076
= 0.06154
B) A component fails in the interval from 1000 to 2000 hours:
P(1000>x>2000) =1 − e^−2000/1076 − 1 +e^−1000/1076 = e^−1000/1076 − e^−2000/1076 = 0.3948 − 0.1559
= 0.2389
C) A component fails before 1000 hours:
P(x<1000) = 0.6052
D) The number of hours at which 10% of all components have failed:
e^−x/1076 = 0.1
= −x/1076
= ln(0.1)
x =(2.3026)×(1076)
x = 2478
21+8+11 equals to 40.
40 is your answer
I hate questions like this. It's like wishing for more wishes.
Now the width is w.
It's twice as long as wide, so now the length is 2w.
If the length is increased by 4 cm, the length will be 2w + 4.
The width is decreased by 3 cm, so the width will be w - 3.
The are of the new rectangle is 100 cm^2.
area = length * width
area = (2w + 4)(w - 3)
The area of the new rectangle is 100, so we get
(2w + 4)((w - 3) = 100
2w^2 - 6w + 4w - 12 = 100
2w^2 - 2w - 112 = 0
w^2 - w - 56 = 0
(w - 8)(w + 7) = 0
w - 8 = 0 or w + 7 = 0
w = 8 or w = -7
A width cannot be negative, so discard w = -7.
w = 8
The width is 8 cm.
The length is twice the width, so the length is 16 cm.
