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3 years ago

What is the probability of getting 60% or better on a true false exam with 50 questions

Mathematics

1 answer:

Ipatiy [6.2K]3 years ago

3 0

Answer:

41.1764...%

Step-by-step explanation:

60% on 50 questions is 30/50 correct since 30÷50=.6=60%

Between 30 and 50(inclusive) there are 21 numbers.(30,31,32...49,50).

There are 51 possibilities of scores,1-50/50 or 0/50

21/51=0.411764...

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A helicopter hovers over a mountain top, and a professional snowboarder drops onto the snow 252525 feet below. the snowboarder's

pantera1 [17]

Given:
h(t) = 25 - a·t²
h(0.5) = 21

Find:
t such that h(t) = 0

Solution:
h(0.5) = 25 - a·0.5² = 21
25 - 21 = a/4
4·4 = a = 16
Then
h(t) = 25 - 16t²
We want h(t) = 0, so
0 = 25 - 16t²
16t² = 25
t² = 25/16 = (5/4)²
t = 5/4 = 1.25

It takes 1.25 seconds for the entire 25 ft drop.

8 0

3 years ago

Robin and Shaon got 5/6 and 4/5 of the total marks. Robin obtained 30 more marks than Shaon.What is the total marks?

Natasha2012 [34]

Answer:

Robin= 750

Sharon= 720

Step-by-step explanation:

let the total marks obtained be X

from question, Robin = 5X/6

Shaon= 4X/5

then, 5X/6= 4X/5+30

or, 5X/6= 4X+150/5

or 25X=24x+900

or,X= 900

therefore robin=750

Shaon = 720

3 0

3 years ago

The shape is composed of three squares and two semicircles.Select all the expressions that correctly calculate the perimeter of

lidiya [134]

Answer:

100+20π

Step-by-step explanation:

Find the diagram attached.

Perimeter of a square =4L

L is the side length of a square

From the diagram;

L = 10

Perimeter of a square = 4(10) = 40

Perimeter of 3 squares = 3(40) = 120

2 semi circle = a circle

Perimeter of a circle= 2πr

radius of the Circle = length of a side of the square.

Area of the circle = 2π(10)= 20π

Perimeter of the shape = Perimeter of the two semicircle + area of the 4squares = 100+20π

3 0

3 years ago

How do I solve this using the substitution method 3x+2y=9 x-5y=4

Harlamova29_29 [7]

$\bf \begin{cases} 3x+2y=9\\ x-5y=4 \end{cases} \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{solving the 2nd equation for "y"}}{x-5y = 4\implies x-4-5y=0}\implies x-4=5y\implies \cfrac{x-4}{5}=y \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{substituting on the 1st equation}}{3x+2\left(\cfrac{x-4}{5} \right) = 9}\implies 3x+\cfrac{2(x-4)}{5}=9 \\\\\\ \stackrel{\textit{multiplying both sides by }\stackrel{LCD}{5}}{5\left( 3x+\cfrac{2(x-4)}{5} \right)=5(9)}\implies 15x+2(x-4)=45$

$\bf 15x+2x-8=45\implies 17x-8=45\implies 17x=53\implies \boxed{x=\cfrac{53}{17}} \\\\\\ \stackrel{\textit{we know that}}{\cfrac{x-4}{5}=y}\implies \cfrac{\left(\frac{53}{17} -4 \right)}{5}=y\implies \cfrac{\left(\frac{53-68}{17} \right)}{5}=y\implies \cfrac{~~\frac{-15}{17}~~}{5}=y \\\\\\ \cfrac{~~\frac{-15}{17}~~}{\frac{5}{1}}=y\implies \cfrac{-15}{17}\cdot \cfrac{1}{5}=y\implies \boxed{-\cfrac{3}{17}=y} \\\\[-0.35em] ~\dotfill\\\\ ~\hfill \left( \frac{53}{17}~~,~~-\frac{3}{17} \right)~\hfill$

8 0

3 years ago

Read 2 more answers

A movie theater sold 40 juice boxes. The cashier noticed that 75% of the boxes were apple juice.

lozanna [386]

30 of them would be apple juice boxes.

40 x 75% = 30

3 0

4 years ago