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Find the sum of the positive integers less than 200 which are not multiples of 4 and 7

taurus [48]

Answer:

$12942$ is the sum of positive integers between $1$ (inclusive) and $199$ (inclusive) that are not multiples of $4$ and not multiples $7$ .

Step-by-step explanation:

For an arithmetic series with:

$a_1$ as the first term,
$a_n$ as the last term, and
$d$ as the common difference,

there would be $\displaystyle \left(\frac{a_n - a_1}{d} + 1\right)$ terms, where as the sum would be $\displaystyle \frac{1}{2}\, \displaystyle \underbrace{\left(\frac{a_n - a_1}{d} + 1\right)}_\text{number of terms}\, (a_1 + a_n)$ .

Positive integers between $1$ (inclusive) and $199$ (inclusive) include:

$1,\, 2,\, \dots,\, 199$ .

The common difference of this arithmetic series is $1$ . There would be $(199 - 1) + 1 = 199$ terms. The sum of these integers would thus be:

$\begin{aligned}\frac{1}{2}\times ((199 - 1) + 1) \times (1 + 199) = 19900 \end{aligned}$ .

Similarly, positive integers between $1$ (inclusive) and $199$ (inclusive) that are multiples of $4$ include:

$4,\, 8,\, \dots,\, 196$ .

The common difference of this arithmetic series is $4$ . There would be $(196 - 4) / 4 + 1 = 49$ terms. The sum of these integers would thus be:

$\begin{aligned}\frac{1}{2}\times 49 \times (4 + 196) = 4900 \end{aligned}$

Positive integers between $1$ (inclusive) and $199$ (inclusive) that are multiples of $7$ include:

$7,\, 14,\, \dots,\, 196$ .

The common difference of this arithmetic series is $7$ . There would be $(196 - 7) / 7 + 1 = 28$ terms. The sum of these integers would thus be:

$\begin{aligned}\frac{1}{2}\times 28 \times (7 + 196) = 2842 \end{aligned}$

Positive integers between $1$ (inclusive) and $199$ (inclusive) that are multiples of $28$ (integers that are both multiples of $4$ and multiples of $7$ ) include:

$28,\, 56,\, \dots,\, 196$ .

The common difference of this arithmetic series is $28$ . There would be $(196 - 28) / 28 + 1 = 7$ terms. The sum of these integers would thus be:

$\begin{aligned}\frac{1}{2}\times 7 \times (28 + 196) = 784 \end{aligned}$ .

The requested sum will be equal to:

the sum of all integers from $1$ to $199$ ,
minus the sum of all integer multiples of $4$ between $1\!$ and $199\!$ , and the sum integer multiples of $7$ between $1$ and $199$ ,
plus the sum of all integer multiples of $28$ between $1$ and $199$ - these numbers were subtracted twice in the previous step and should be added back to the sum once.

That is:

$19900 - 4900 - 2842 + 784 = 12942$ .

8 0

3 years ago

How to solve function operations

Mama L [17]

" Given f (x) = 3x + 2 and g(x) = 4 – 5x, find (f + g)(x), (f – g)(x), (f × g)(x), and (f / g)(x).1. = [3x + 2] + [4 – 5x] = 3x + 2 + 4 – 5x. = 3x – 5x + 2 + 4. = –2x + 6. (f – g)(x) 2. = f (x) – g(x)= [3x + 2] – [4 – 5x] = 3x + 2 – 4 + 5x. = 3x + 5x + 2 – 4. = 8x– 2. 3. ...= (3x + 2)(4 – 5x) = 12x + 8 – 15x2 – 10x. = –15x2 + 2x + 8. " - Google

3 0

2 years ago

Factor 16xy^2-24y^2z+40y^2

qaws [65]

Answer:

8y^2(2x_3z+5)

.......

3 0

3 years ago

How to solve this one

Stells [14]

Answer:

(-5,1)

Step-by-step explanation:

Add it together

3x - 2x = x

y - y = 0

9 - 14 = -5

x = -5

Choose a random equation, doesn't matter.

3x + y = -14

3(-5) + y = -14

-15 + y = -14

y = -14 + 15

y = 1

7 0

2 years ago

Read 2 more answers

Find all real solutions of the equation. (if there is no real solution, enter no real solution.) 35x2 12x − 36

solmaris [256]

Important: 35x2 12x − 36 is not an equation; to obtain an equation, you must set <span>35x2 12x − 36 = to 0:

</span><span>35x^2 + 12x − 36 = 0. Also, "the square of x" must be represented by "x^2," and you must insert either the + or the - sign in front of the term 12x.

I am assuming that you meant </span>35x^2 + 12x − 36 = 0.

If that is indeed the case, then a = 35, b = 12 and c = -36

and the discriminant is b^2 - 4ac, or (12)^2 - 4(35)(-36) = 5184.

Since the discriminant is positive, this equation has 2 real, unequal solutions. They are
-12 plus or minus sqrt(5184)
x = -----------------------------------------
2(35)

7 0

3 years ago