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3 years ago

36 boys complete a school task in 4 hours. How many boys would be required to complete the same task in 2¼ hours?

Mathematics

1 answer:

vova2212 [387]3 years ago

8 0

Answer:

Step-by-step explanation:

If 36 boys can conplete a task in 4 hours, then 19.35 boys could do it in 2 and a fourth hours.

You can set up an equation

A fourth of an hour is 15 minutes, so,

36 is to 4 as x is to 2.15, or,

36=4 as X=2.15

Multiply 2.15 by 36 (77.4)

77.4 divided by 4= 19.35.

Of course, you cannot have 19.35 boys, so there must be 20.

Hope this helps!

You might be interested in

Consider the equality xy k. Write the following inverse proportion: y is inversely proportional to x. When y = 12, x=5.

skelet666 [1.2K]

Answer:

$y=\dfrac {60} {x}$ or $xy=60$ (depending on your teacher's format preference)

Step-by-step explanation:

<h3><u>Proportionality background</u></h3>

Proportionality is sometimes called "variation". (ex. " 'y' varies inversely as 'x' ")

There are two main types of proportionality/variation:

Direct
Inverse.

Every proportionality, regardless of whether it is direct or inverse, will have a constant of proportionality (I'm going to call it "k").

Below are several different examples of both types of proportionality, and how they might be stated in words:

$y=kx$ y is directly proportional to x
$y=kx^2$ y is directly proportional to x squared
$y=kx^3$ y is directly proportional to x cubed
$y=k\sqrt{x}}$ y is directly proportional to the square root of x
$y=\dfrac {k} {x}$ y is inversely proportional to x
$y=\dfrac {k} {x^2}$ y is inversely proportional to x squared

From these examples, we see that two things:

things that are <u>directly proportional</u> -- the thing is <u>multipli</u>ed to the constant of proportionality "k"
things that are <u>inversely proportional</u> -- the thing is <u>divide</u>d from the constant of proportionality "k".

<h3><u>Looking at our question</u></h3>

In our question, y is inversely proportional to x, so the equation we're looking at is the following $y=\dfrac {k} {x}$ .

It isn't yet clear what the constant of proportionality "k" is for this situation, but we are given enough information to solve for it: "When y=12, x=5."

We can substitute this known relationship pair, and find the "k" that relates this pair of numbers:

<h3><u>Solving for k, and finding the general equation</u></h3>

General Inverse variation equation...

$y=\dfrac {k} {x}$

Substituting known values...

$(12)=\dfrac {k} {(5)}$

Multiplying both sides by 5...

$(12)*5= \left ( \dfrac {k} {5} \right ) *5$

Simplifying/arithmetic...

$60=k$

So, for our situation, k=60. So the inverse proportionality relationship equation for this situation is $y=\dfrac {60} {x}$ .

The way your question is phrased, they may prefer the form: $xy=60$

7 0

2 years ago

Kelsey has a little baby brother he weighs 8 pounds in 3 ounces the doctor said the baby should get about 5 ounces per week at t

Virty [35]

Answer:

11.9375 and just round it

Step-by-step explanation:

multiply 8 pounds to 16 to get ounces and then add three and 60(5 x 12) and then add all of it together and then divide it to 16 to get 11.94 pounds or however you want to round it. If you need more a more deeper explanation just ask.

4 0

3 years ago

a large basket of apples weighed 10 2/3lb. if the weight of the basket was 1 1/4lb, how much did the apples weigh?

dolphi86 [110]

A large basket of apples weighed 10 2/3lb

Basket was 1 1/4lb

Apples weigh = 10 2/3 - 1 1/4

Apples weigh = 10 8/12 - 1 3/12

Apples weigh = 9 5/12

Answer

Apples weighed 9 5/12 lbs

7 0