If you know the answer, please respond! I've been stuck on this question for the longest time
A fuel injection system is designed to last 18 years, with a standard deviation of 1.4 years. What is the probability that a fuel injection system will last less than 15 years?
A. 25%
B. 33%
C. 2%
D. 20%

C. 2%

Step-by-step explanation:

The question is asking the probability that the result is <15 years. The fuel injection system mean is 18 years with 1.4 years of standard deviation(SD). If you convert the desirable result into mean +/- SD it will be:

15 years = mean +/- x SD

15 years= 18 years +/-x 1.4 years

x= -3 years/1.4 years= - 2.14 SD

After this, you can find the z-score of -2.14 SD, which is 0.0162 = 1.62%. The closest answer is C.

Without the Z-score table, you can also predict the answer by using the 68-95-99.7 rule. Since its around 2SD away (2SD= 95%) and you only take -2 SD (not taking +2SD ), it will be  (100%-95%)/2= 2.5%

something that characterises a right triangle is the fact that we may use pythagoras' theorem to find any one of its sides given that we have the length of the other two sides. here, we have the length of the hypotenuse, √(87) yd, and one other side, √(23) yd, thus we can easily find the length of the remaining side using pythagoras' theorem as defined below:

c^2 = a^2 + b^2, where c is the length of the hypotenuse, and a and b are the lengths of the other two sides.

thus, given that c = √(87) and a = √(23), we may substitute these into the formula we defined above to get:

c^2 = a^2 + b^2

(√87)^2 = (√23)^2 + b^2 (substitute c = √87 and a = √23 into the equation)

87 = 23 + b^2 (evaluate (√87)^2 = 87 and (√23)^2 = 23 - remember that the square root of a number, squared will equal that very same number)

64 = b^2 (subtract 23 from both sides)

√64 = b (take the square root of both sides)

8 = b (evaluate √64 = 8)

therefor, the length of the unknown leg in the right triangle is 8 yd (first answer).

1. perpendicular

2. parallel

3. perpendicular