Step-by-step explanation:
The model will contain 1 ten and 4 ones in each group.
Please provide details such as the word problem and options.
Answer:
Step-by-step explanation:
The first differences of the sequence are ...
- 5-2 = 3
- 10-5 = 5
- 17-10 = 7
- 26-17 = 9
- 37-26 = 11
Second differences are ...
- 5 -3 = 2
- 7 -5 = 2
- 9 -7 = 2
- 11 -9 = 2
The second differences are constant, so the sequence can be described by a second-degree polynomial.
We can write and solve three equations for the coefficients of the polynomial. Let's define the polynomial for the sequence as ...
f(n) = an^2 + bn + c
Then the first three terms of the sequence are ...
- f(1) = 2 = a·1^2 + b·1 + c
- f(2) = 5 = a·2^2 +b·2 + c
- f(3) = 10 = a·3^2 +b·3 +c
Subtracting the first equation from the other two gives ...
3a +b = 3
8a +2b = 8
Subtracting the first of these from half the second gives ...
(4a +b) -(3a +b) = (4) -(3)
a = 1 . . . . . simplify
Substituting into the first of the 2-term equations, we get ...
3·1 +b = 3
b = 0
And substituting the values for a and b into the equation for f(1), we have ...
1·1 + 0 + c = 2
c = 1
So, the formula for the sequence is ...
f(n) = n^2 + 1
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The 20th term is f(20):
f(20) = 20^2 +1 = 401
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<em>Comment on the solution</em>
It looks like this matches the solution of the "worked example" on your problem page.
A stem and leaf plot shows sets of two digit numbers, by separating the ten’s place and the one’s place. On the left is the different ten’s values, while on the right next to each of the values on the left is the one’s values that associate with each of the ten’s values. This means that the numbers in this set of data are 32, 47, 51, 55, 55, 55, 58, 64, and so on. From there, you can use that knowledge to figure out how many scores were above 60.
The terms that are above 60 are 64, 65, 73, 74, 77, 87, 88, 91, 93, 93, 97, 99, and 99, for a total of 13 of the 20 scores being above 60.
