All categories

2 years ago

The sum of four numbers is 20 and their average is 5. When a fifth is added, the new average is 6. What is the fifth number?

Mathematics

2 answers:

ipn [44]2 years ago

8 0

Answer:

Step-by-step explanation:

We'll note the numbers as $x_{n}, x_{n+1} ...$

$x_1 + x_2 + x_3 + x_4 = 20\\Avg = 5\\\frac{x_1 + x_2 + x_3 + x_4 + x_5 }{5} = 6 = \frac{20 + x_5}{5}\\ 4 + \frac{x_5}{5} = 6\\\\frac{x_5}{5} = 2\\\x_5 = 10$

Mama L [17]2 years ago

3 0

Answer:

10.

Step-by-step explanation:

The average of the 5 numbers =

(20 + x) / 5 = 6 where x is the 5th number.

20 + x = 30

x = 10

The fifth number is 10.

You might be interested in

Use the elimination method to find all solutions of the system:

weqwewe [10]

Answer:

$x = 3$ and $y = 4$

Step-by-step explanation:

Given

[Correct Question]

$x^2 - 2y = 1$

$x^2 + 5y = 29$

Required

Solve using elimination

First, we eliminate x.

Subtract equation (1) from (2)

$x^2 - x^2 + 5y - (-2y) = 29 - 1\\$

$5y - (-2y) = 28$

$5y +2y = 28$

$7y = 28$

Divide through ny 7

$y = 4$

Take $x^2 - 2y = 1$

Make x^2 the subject

$x^2 = 1 + 2y$

Substitute 4 for y

$x^2 = 1 + 2*4$

$x^2 = 1 + 8$

$x^2 = 9$

Take square roots

$x = \sqrt 9$

$x = 3$

7 0

2 years ago

I will fan and medal if you help!

Annette [7]

Part A: The answer is B.
As vertically opposite angles are equal
x+10=4x-35
10=3x-35
45=3x
x=15

Part B: The answer is D.
We'll substitute in the value of X in one equation.
x+10
=15+10
=25
As the two angles are equal bot must be 25 degrees.

8 0

2 years ago

What is the area of the figure?

masya89 [10]

Step-by-step explanation:

∆=3*6=18

[]=5*15=75

75+18=93 in squared

3 0

3 years ago

Calculate the capacity in liters of a tin 20m by 15m by 10m.

rusak2 [61]