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2 years ago

Share £60 in the ratio 1:4

Mathematics

1 answer:

soldi70 [24.7K]2 years ago

8 0

Answer:

s=5

v=2

Step-by-step explanation:

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A random sample of the amounts for 22 purchases was taken. The mean was $42.97, the standard deviation was $22.82, and the m

Illusion [34]

Answer: a) 84 and b ) 2084

Step-by-step explanation:

Given : Sample standard deviation : s= $22.82

(Population standard deviation is unknown ) , so we use t-test.

Critical value or the 95% confidence intervals : $t_{n-1}*=2.0$

Formula to find the sample size :

$n=(\dfrac{t^*\cdot s}{E})^2$

a) E = 5

$n=(\dfrac{(2)\cdot 22.82}{5})^2$

$n=(9.128)^2=83.320384\approx84$

i.e. Required sample size : n= 84

b) E = 1

$n=(\dfrac{(2)\cdot 22.82}{1})^2$

$n=(45.64)^2=2083.0096\approx2084$

i.e. Required sample size : n= 2084

8 0

2 years ago

5. Find the discriminant of 15x2 = 4x – 1 and describe

diamong [38]

Answer:

a) The discriminant of the equation = - 44

b)The nature of the roots will be imaginary.

c) $x = \frac{2 +\sqrt{11} i}{15} or, x = \frac{2 - \sqrt{11} i}{15}$

Step-by-step explanation:

Here, the given expression is $15x^{2} = 4x -1$

or, $15x^{2} - 4x + 1 = 0$

Now the discriminant (D) of a quadratic equation $ax^{2} +b x + c = 0$

D = $b^{2} - 4ac = (-4)^{2} - 4(15) (1) = 16 - (60) = -44$

Hence, the discriminant of the equation = - 44

As D< 0, so the roots will be imaginary.

Now,by quadratic formula : $x = \frac{-b \pm \sqrt{b^{2} - 4ac} }{2a}$

So, here $x = \frac{-(-4) \pm \sqrt{D} }{2a} = \frac{4 \pm \sqrt{(-44 )} }{30}$

So, either $x = \frac{4 + \sqrt{(-44 )} }{30} or, x = \frac{4 - \sqrt{(-44 )} }{30}$

or, $x = \frac{2 +\sqrt{11} i}{15} or, x = \frac{2 - \sqrt{11} i}{15}$

8 0

2 years ago

Jeannie got a new pair of eye glasses. She was able to pay $15 at the time

Lisa [10]

Answer:

6 months, i used the equation from part a so i know it’s right

Step-by-step explanation:

a) 15 + 12x = 87

b) 12x = 87-15=72

72/12 = 6

3 0

2 years ago

Read 2 more answers

What type of covalent bond diagram only shows the outer shell of electrons?

vitfil [10]

Correct answer: <span>Dot-and-cross-diagram
</span>

Dot-and-cross diagrams are used to represent covalent bonds. The shared electron from one atom is shown as a dot, while the shared electron from the other atom is shown as a cross.

When drawing dot-and-cross diagrams for covalent bonds, you only need to show the electrons in the highest occupied energy level, as only these are involved.

4 0

3 years ago

Someone please help.

olga55 [171]

Answer:

Step-by-step explanation:

It's solved by grafic method

6 0

2 years ago