Given the arithmetic series a1+a2+a3+a4 a 1 + a 2 + a 3 + a 4 8 + 11 + 14 + 17 + . . + 68 what is the value of sum?

Here the first term, a = 8, common difference, d= 11-8= 3 and the last term , l = 68

So before finding the sum, first we need to find the number of terms, and for that we use the formula

a(n) = a+(n-1)d

68 = 8+(n-1)3

Subtracting 8 from both sides

60 = (n-1)3

Dividing both sides by 3

20=n-1

Adding 1 to both sides

n =21

Now we use the formula of sum of n terms of arithmetic series, which is

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation:

7.25

step-by-step explanation:

we know that 7 equals to 7.0. we also know that 1/4=0.25. so we can add the two together and we get 7.25