Answer:
a₄ = - 15
Step-by-step explanation:
Using the recursive formula and a₁ = 17 , then
a₂ = a₁ - 8 = 17 - 8 = 9
a₃ = a₂ - 8 = 9 - 8 = 1
a₃ = a₂ - 8 = 1 - 8 = - 7
a₄ = a₃ - 8 = - 7 - 8 = - 15
Answer:

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

And replacing we got:


We can find the probability of interest using the normal standard table and with the following difference:

Step-by-step explanation:
Let X the random variable who represent the expense and we assume the following parameters:

And for this case we want to find the percent of his expense between 38.6 and 57.8 so we want this probability:

And we can assume a normal distribution and then we can solve the problem with the z score formula given by:

And replacing we got:


We can find the probability of interest using the normal standard table and with the following difference:

You have to find the area of both the square and rectangle. use the formula A=wl
square = 3x3 = 9
rectangle = 10x3 = 30
area= 39 (i think)
Answer:
I don't know
Step-by-step explanation:
because I don't see the pattern