C is the answer because a number of children are unknown.
Answer:
mCEA = 90ᴼ because CEA is a right angle, and right angles have 90ᴼ measures.
CEF is a straight angle because there are two 90ᴼ angles (CEA and AEF) and therefore there is 180ᴼ in total. A straight line has a measure of 180ᴼ.
AEF is a right angle because if CEA is a right angle and CEF is a straight line, then AEF has to be a right angle.
Coefficient of variation is calculated by dividing the standard deviation by the mean multiplied by 100. Given a data set with mean equal to 60 and variance equal to 9, we can calculate the coefficient of variation by finding the value of the standard deviation which is the square root of the variance. so standard deviation is equal to square root of 9 which is 3. Then, the coefficient of variation is equal to 3/60*100 which is equal to 5%.
we are given the probability that is 88% of person A speaking the truth. The probability of person B speaking the truth on an occasion that person A also speaks the truth is 43%. This means the probability that person A speaks the truth, but person B lies 0.88*(1-0.43) equal to 0.5016
