Answer:
The answer is A...
Step-by-step explanation:
Brainliest?
Let's do subtraction by first starting with the ones place and then the tenths place of the subtrahend.
45-4=41; 44, 43, 42, 41
41-.5= 40.5; 40.9, 40.8, 40.7, 40.6, 40.5
45-4.5=40.5
We can check by using addition.
40.5+4.5=
44+1=
45
If 39 = (1 3/10)b, we could simplify this by writing 39 - (13/10)b.
Solve this for b by mult. both terms by (10/13):
(10*39)
----------- = (10/13)(13/10)b. Then b = 30 (answer)
13
Answer:

--- Variance
Step-by-step explanation:
Given

Solving (a): Calculate the mean.
The given data is a grouped data. So, first we calculate the class midpoint (x)
For 51 - 58.

For 59 - 66

For 67 - 74

For 75 - 82

For 83 - 90

So, the table becomes:

The mean is then calculated as:



-- approximated
Solving (b): The sample variance:
This is calculated as:

So, we have:


-- approximated
10.2 all you have to do is add up all the sides... hope this helps!