Answer: C.-1.5
Step-by-step explanation:
Given: The burning time of a very large candle is normally distributed with mean
of 2500 hours and standard deviation
of 20 hours.
Let X be a random variable that represent the burning time of a very large candle.
Formula: 
For X = 2470

So, the z-score they corresponds to a lifespan of 2470 hours. =-1.5
Hence, the correct option is C.-1.5.
The determinant of a 2 x 2 matrix can be calculated as:
Product of non-diagonal elements subtracted from product of diagonal elements.
The diagonal elements in given matrix are 12 and 2. The non-diagonal elements are -6 and 0.
So,
Determinant G = 12(2) - (-6)(0)
Determinant G = 24 - 0 = 24
So, option B gives the correct answer
Answer: D I think
Step-by-step explanation:
Part A: W = 10x
Part B: S = 400 + 15y
Part C: 490 = 400 +15y
-400 -400
90 = 15y
6 = y, so he worked a total of 46 hours.
the answer is 63 because 63*2=126 and 126+54=180 and all triangles add up to 180