All categories

2 years ago

The mean of four numbers is 6. Three of them are 3.4,10.7and 7.8. what is the fourth number?

Mathematics

2 answers:

Marianna [84]2 years ago

8 0

Answer:

2.1

Step-by-step explanation:

Use the equation

Sum of elements = average x number of elements

sum = (6)(4)

sum = 24

Add up the numbers we know: 3.4 + 10.7 + 7.8 = 21.9

24 - 21.9 = 2.1

This means the fourth number is 2.1

iren2701 [21]2 years ago

7 0

Answer:

2.1

Step-by-step explanation:

Let x be the 4th number. To find the mean add the 4 numbers and divide by 4

( 3.4 + 10.7+7.8+x) /4 = 6

Multiply each side by 4

( 3.4 + 10.7+7.8+x) /4 *4= 6*4

( 3.4 + 10.7+7.8+x) = 24

Combine like terms

x+21.9=24

Subtract 21.9 from each side

x = 24-21.9

x =2.1

You might be interested in

Is 1/2 or 4/8 bigger???

PIT_PIT [208]

Answer: they are both the same fraction

3 0

2 years ago

24h-36? Need helppp please

FinnZ [79.3K]

The trick question is that you can’t effect an unknown value because you don’t know what number it is, it has to be a known value, there is nothing that you can do to figure it out, so it’s unknown and cannot be effected.

7 0

2 years ago

Solve the following system by any method -8x-8y=0 -8x+2y=-20

iVinArrow [24]

$\fbox{Solution by using Matrix}$

$\text{Linear Equation} = -8x-8y=0 , -8x+2y=-20$

$\text{Rewrite the linear equations above as a matrix}$

$\left[\begin{array}{ccc}8&-8&0\\-8&2&-20\\\end{array}\right]$

$\text{Apply to Row2 : Row2 + Row1}$

$\left[\begin{array}{ccc}8&-8&0\\-8&-6&-20\\\end{array}\right]$

$\text{ Simplify rows}$

$\left[\begin{array}{ccc}8&-8&0\\0&1&10/3\\\end{array}\right]$

$\text{Note: The matrix is now in echelon form.}$ $\text{The steps below are for back substitution.}$

$\text{Apply to Row1 : Row1 + 8 Row2}$

$\left[\begin{array}{ccc}8&0&80/30\\0&1&10/3\\\end{array}\right]$

$\text{ Simplify rows}$

$\left[\begin{array}{ccc}1&0&10/3\\0&1&10/3\\\end{array}\right]$

$\text{Therefore, the solution is}$

$x= \dfrac{10}{3} \ \text{and} \ \ y=\dfrac{10}{3}$

7 0

2 years ago

Pls help! 16 points:)

kenny6666 [7]

Answer: 52 degrees

Step-by-step explanation:

most likley like if correct

7 0

2 years ago

Read 2 more answers

Hi! Please help, I'd appreciate it!

Romashka-Z-Leto [24]