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3 years ago

The class average on a test was about 86% or 19 questions correct. How many questions were on the test?

Mathematics

1 answer:

astraxan [27]3 years ago

3 0

Answer:

I think the answer is 35 but im not positve

Step-by-step explanation:

hope this helps :)

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The length of a swimming pool is 8 m longer than it's width and the area is 105m²

Art [367]

width= 7m

Step-by-step explanation:

Area= L×W

L= (x+8)m

W=8m

105m²= (x+8)m × (x)m

105m²= x² + 8x

-x² - 8x + 105= 0

(x-7) (x+15) = 0

x= 7 x= -15

x=width = 7m

6 0

3 years ago

Read 2 more answers

NASA launches a rocket at t = 0 seconds. Its height, in meters above sea-level, as a function of time is given by h ( t ) = − 4.

Oliga [24]

Answer:

$\displaystyle 1)48.2 \: \: \text{sec}$

$\rm \displaystyle 2)3021.6 \: m$

Step-by-step explanation:

<h3>Question-1:</h3>

so when flash down occurs the rocket will be in the ground in other words the elevation(height) from ground level will be 0 therefore,

to figure out the time of flash down we can set h(t) to 0 by doing so we obtain:

$\displaystyle - 4.9 {t}^{2} + 229t + 346 = 0$

to solve the equation can consider the quadratic formula given by

$\displaystyle x = \frac{ - b \pm \sqrt{ {b}^{2} - 4 ac} }{2a}$

so let our a,b and c be -4.9,229 and 346 Thus substitute:

$\rm\displaystyle t = \frac{ - (229) \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

remove parentheses:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

simplify square:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 4( - 4.9)(346)} }{2.( - 4.9)}$

simplify multiplication:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 6781.6} }{ - 9.8}$

simplify Substraction:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 45659.4} }{ - 9.8}$

by simplifying we acquire:

$\displaystyle t = 48.2 \: \: \: \text{and} \quad - 1.5$

since time can't be negative

$\displaystyle t = 48.2$

hence,

at 48.2 seconds splashdown occurs

<h3>Question-2:</h3>

to figure out the maximum height we have to figure out the maximum Time first in that case the following formula can be considered

$\displaystyle x _{ \text{max}} = \frac{ - b}{2a}$

let a and b be -4.9 and 229 respectively thus substitute:

$\displaystyle t _{ \text{max}} = \frac{ - 229}{2( - 4.9)}$

simplify which yields:

$\displaystyle t _{ \text{max}} = 23.4$

now plug in the maximum t to the function:

$\rm \displaystyle h(23.4)- 4.9 {(23.4)}^{2} + 229(23.4)+ 346$

simplify:

$\rm \displaystyle h(23.4) = 3021.6$

hence,

about 3021.6 meters high above sea-level the rocket gets at its peak?

5 0

3 years ago

Xavier is a new student, explain to him what a variable is. Use complete sentences.

Anit [1.1K]

Answer:a symbol, usually a letter, used to represent a number.

Step-by-step explanation:

a math process (like adding, subtracting, multiplying, or dividing)

3 0

3 years ago

Freeeeeeeeeeeeeeeeee again

Paraphin [41]

Answer:

cool

Step-by-step explanation:

3 0

4 years ago

Read 2 more answers

Which words make this statement true?

yan [13]

-4 is Less than -3 is the answer

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3 years ago