In a class of 30, five were absent. What fraction of the class was absent?

Mathematics

1 answer:

kipiarov [429]2 years ago

3 0

5/30 were absent or 1/6 simplifying or dividing both by 5 we have: 1/6

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A tool and die company buys a machine for 175,000 and it depreciates at a rate of 30% per year. Find the depreciated value of th

DaniilM [7]

1417.5 is the answer and this is a tricky question.

8 0

2 years ago

An air traffic controller spots two airplanes at the same altitude converging to a point as they fly at right angles to each oth

sattari [20]

They are traveling at right angles to each other so we can say one is traveling north to south and the other west to east. Then we can say that there positions, y and x are:

y=150-600t x=200-800t

By using the Pythagorean Theorem we can find the distance between these two planes as a function of time:

d^2=y^2+x^2, using y and x from above

d^2=(150-600t)^2+(200-800t)^2

d^2=22500-180000t+360000t^2+40000-320000t+640000t^2

d^2=1000000t^2-500000t+62500

d=√(1000000t^2-500000t+6250)

So the rate of change is the derivative of d

dd/dt=(1/2)(2000000t-500000)/√(1000000t^2-500000t+6250)

dd/dt=(1000000t-250000)/√(1000000t^2-500000t+6250)

So the rate depends upon t and is not a constant, so for the instantaneous rate you would plug in a specific value of t...

...

To find how much time the controller has to change the airplanes flight path, we only need to solve for when d=0, or even d^2=0...

1000000t^2-500000t+62500=0

6250(16t^2-8t+1)=0

6250(16^2-4t-4t+1)=0

6250(4t(4t-1)-1(4t-1))=0

6250(4t-1)(4t-1)=0

6250(4t-1)^2=0

4t-1=0

4t=1

t=1/4 hr

Well technically, the controller has t<1/4 because at t=1/4 impact will occur :)

7 0

2 years ago

Amelie is making a recipe that uses 1 3/4 cups flour. She is making 2 1/2 times the original recipe.

elixir [45]

Answer:

She would need $4\frac{3}{8}$ flour to make $2\frac{1}{2}$ times the recipe.

Step-by-step explanation:

To make 1 recipe Amelia uses = $1 \frac{3}{4}\ cups$ of flour.

So, to make $2\frac{1}{2}$ times the recipe she would need = $1 \frac{3}{4}\times 2\frac{1}{2}$ .

We evaluate the above mixed numbers by converting them to fraction(by multiplying denominator with whole number and adding to numerator and write as fraction of same denominator.).

$=\frac{7}{4}\times \frac{5}{2}$

$=\frac{35}{8}$

Then converting back to mixed number (by dividing the numerator by denominator and writing the quotient as the whole number and the remainder as fraction with same denominator.

$\frac{35}{8}=4\frac{3}{8}$