1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
tatuchka [14]
4 years ago
7

PLLLZ HELP Find Sn if a1 = 20, d = –10, and n = 25.

Mathematics
2 answers:
Ivanshal [37]4 years ago
8 0

Option A: -2500 is the value of S_{25

Explanation:

It is given that the first term is a_1=20

The common difference is d=-10

We need to determine the sum of 25 terms.

The sum of  terms of an arithmetic series can be determined using the formula, S_n=\frac{n[2a_1+(n-1)d]}{2}

Substituting n=25 , a_1=20 and d=-10

Thus, we have,

S_{25}=\frac{25[2(20)+(25-1)(-10)]}{2}

Simplifying the values, we get,

S_{25}=\frac{25[40+(24)(-10)]}{2}

S_{25}=\frac{25[40-240]}{2}

Subtracting the terms within the bracket, we get,

S_{25}=\frac{25[-200]}{2}

Multiplying the terms in the numerator, we have,

S_{25}=\frac{-5000}{2}

Dividing, we get,

S_{25}=-2500

Thus, the sum of the 25 terms is -2500

Therefore, Option A is the correct answer.

Andru [333]4 years ago
6 0

Answer:

-2500 answer

Step-by-step explanation:

You might be interested in
To make 1 1/2 ozen muffins a recipe uses 3 1/2 cups of flour how many cups of flour is needed for every dozen muffins made
Ahat [919]

Answer:

the answer is 2 1/3 or There is 2\frack{11}{14}\ cups needed to make every dozen of muffins.

Step-by-step explanation:

Hope this helps:)

3 0
3 years ago
Read 2 more answers
HELP! Which triangles are congruent?
kati45 [8]

9514 1404 393

Answer:

  4.  A, B, C, and D

Step-by-step explanation:

Each right triangle has a short leg of 3 units and a long leg of 4 units. They are all congruent by the SAS congruence postulate.

8 0
3 years ago
5 decenas de millón, 8 centenas de millar
Kay [80]

Answer:

sorry, i do not know

Step-by-step explanation:

i

8 0
3 years ago
The net of a pyramid is shown below. The surface area of the solid is ____ square inches.
Effectus [21]
Area of a triangle= bh/2b=4in h=8in8x4/2=16in
there are 4 triangles
4x16=64
area of a rectangle=bh
4x4=16
64+16=80in^2
5 0
4 years ago
Read 2 more answers
0. The weight of an object on the Moon is about 16.5% of its weight on Earth. The weight of an astronaut on the Moon is 24.75 po
Setler79 [48]

Answer: 150 pounds

Step-by-step explanation:

Let the the astronaut weight on Earth be represented by x.

Based on the information given in the question, thus can be formed into an equation as:

16.5% of x = 24.75

16.5% × x = 24.75

16.5/100 × x = 24.75

0.165x = 24.75

x = 24.75/0.165

x = 150 pounds

The astronaut weigh 150 pounds on Earth.

3 0
3 years ago
Other questions:
  • a plane can fly 7 miles per minute. the plane will fly 8 trips, and each trip is 810 miles. how many hours will the plane fly? s
    9·1 answer
  • What's the answer ?????
    7·1 answer
  • If sally has 566 books but has 5 box’s how many books goes into each box?
    14·2 answers
  • scott has a travel book on each of four Hawaiian: Maui, Kauai, Hawaii, and Oahu. In how many different ways can these four books
    7·2 answers
  • The difference of 2 numbers is 2 and their product is 80<br>Please respond quick
    15·2 answers
  • Please please pleaseeeeeeee help me thx
    11·2 answers
  • I need help with slope
    12·1 answer
  • Y = -1/2x + 2.5 (no answer options)
    14·1 answer
  • Complete the following questions. 4 x 5 - 45 ÷ 9 = (18 - 6) x (12 - 4) =
    5·2 answers
  • A cylinder with radius 2 units is shown below. Its volume is 75 cubic units. Find the height of the cylinder.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!