A certain type of concrete mix is designed to withstand 3000 pounds per square inch (psi) of pressure. The concrete is poured into casting cylinders and allowed to set for 28 days. The concrete's strength is then measured. The following data represent the strength of nine randomly selected casts (in psi). Compute the mean, median, and mode strength of the concrete (in psi). 3960, 4090, 3200, 3100, 2940, 3830, 4090, 4040, 3780

Step-by-step explanation:

Given the data representation of the strength of nine randomly selected casts (in psi) as 3960, 4090, 3200, 3100, 2940, 3830, 4090, 4040, 3780.

MEAN

Mean is the average of the samples

is thw sum of the given data

N is the sample size

is the mean

Hence the mean of the data is 3,670psi

MEDIAN

Median is the value at the middle of the data after rearrangement.

On rearranging in ascending order

2940, 3100, 3200, 3,780) 3,830 (3,960, 4040, 4090, 4090

It can be seen that the middle value is 3860. Hence the median of the data is 3860psi.

MODE

Mode is the most occurring data in the dataset. It is the data with the highest frequency. From the data, it can be seen that the only data occurring most (twice) is 4090, hence the modal value is 4090psi

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺

answer:   c ?

step-by-step explanation: