The average of 4 numbers is 15 , the sum of 3 numbers is 14 what is the fourth number

Mathematics

2 answers:

Nostrana [21]3 years ago

7 0

Answer:

Step-by-step explanation:

(14+x)/4 = 15

14 + x = 60

x = 46

vladimir1956 [14]3 years ago

6 0

Answer:

Step-by-step explanation:

Let <em>a to d</em> be <em>number 1 to 4</em> respectively.

15 = (a + b + c + d) / 4

(a + b + c + d) = 60 ------> <em>total sum of the 4 numbers</em>

Since the sum of 3 numbers (assuming a to c) is 14,

Fourth number (d) = 60 - 14

= 46

That's how I would do it, hope this helps :)

You might be interested in

If 12 men earn $810 in 10 days how much will 14 men earn in 8 days, if the daily wage is the same for each man

kogti [31]

1 man earns 810 / 12 = $67.5 in 10 days
by proportion 1 man will earn 0.8 * 67.5 = $54 in 8 days

So 14 men will earn 54 * 14 = $756 in 8 days.

5 0

3 years ago

Which expression is a fourth root of -1+isqrt3?

aleksklad [387]

Answer:

Step-by-step explanation:

$\sf n^{th}$ roots of a complex number is given by DeMoivre's formula.

$\sf \boxed{\bf r^{\frac{1}{n}}\left[Cos \dfrac{\theta + 2\pi k}{n}+i \ Sin \ \dfrac{\theta+2\pi k}{n}\right]}$

Here, k lies between 0 and (n -1) ; n is the exponent.

$\sf -1 + i\sqrt{3}$

a = -1 and b = √3

$\sf \boxed{r=\sqrt{a^2+b^2}} \ and \ \boxed{\theta = Tan^{-1} \ \dfrac{b}{a}}$

$\sf r = \sqrt{(-1)^2 + 3^2}\\\\ = \sqrt{1+9}\\\\=\sqrt{10}$

$\sf \theta = tan^{-1} \ \dfrac{\sqrt{3}}{-1}\\\\ = tan^{-1} \ (-\sqrt{3})$

$\sf = \dfrac{-\pi }{3}$

n = 4

For k = 0,

$\sf z = \sqrt[4]{10}\left[Cos \ \dfrac{\dfrac{-\pi}{3} +0}{4}+iSin \ \dfrac{\dfrac{-\pi}{3}+0}{4}\right] \\\\\\z= \sqrt[4]{10} \left[Cos \ \dfrac{ -\pi }{12}+iSin \ \dfrac{-\pi}{12}\right]\\\\\\z = \sqrt[4]{10}\left[-Cos \ \dfrac{\pi}{12}-i \ Sin \ \dfrac{\pi}{12}\right]$