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3 years ago

By which smallast number must the following number be divided so that the quotient is a perfect cube

Mathematics

2 answers:

jenyasd209 [6]3 years ago

8 0

Answer:

Step-by-step explanation:

8640/60 is 144. 144 is a perfect square. 12*12 is 144

True [87]3 years ago

4 0

Hey there! I'm happy to help!

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INTRO TO PERFECT CUBES

A perfect cube is any number whose cube root is an integer. In English, that means that if you take any number without a fraction (this is called an integer, such as -7, 8, 100, none have fractions) and multiply it by itself three times, you get a perfect cube.

If you cube the number 4, you get 64, which is (4×4×4). 64 is an example of a perfect cube.

You can use the cube root button on your calculator to see if a number is a perfect cube. If you do the cube root of 64, you get 4, telling you that 64 is a perfect cube. The cube root of 10 is 2.154434...... so 10 is not a perfect square because it does not give you an integer (number that does not have a fraction) as the answer.

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SOLVING THE PROBLEM

So, we want to find the smallest numbers we can divide 8640 to equal a perfect cube.

I will assume that we will not be dividing by fractions but only whole numbers (positive integers).

We could try dividing by 1, but we see that 8640 is not a perfect cube because it's cube root is 20.519711....

Let's just keep counting up! The first divisor we run into that gives a quotient that it is a perfect cube is the smallest whole number possible that will give us that result.

8640÷2=4320

∛4320≈16.2865....... Not a perfect cube

8640÷3=2880

∛2880≈14.22757..... Not a perfect cube

8640÷4=2160

∛2160≈12.92660..... Not a perfect cube

8640÷5=1728

∛1728=12, a perfect cube!

Since 12 cubed is equal to 1728, this means that 1728 is a perfect square, so 5 is the smallest number we can divide 8640 by to get a perfect square.

The answer is 5.

I hope that this helps! Have a wonderful day! :D

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Suppose a certain computer virus can enter a system through an email or through a webpage. There is a 40% chance of receiving th

DedPeter [7]

Answer:

P = 0.42

Step-by-step explanation:

This probability problem can be solved by building a Venn like diagram for each probability.

I say that we have two sets:

-Set A, that is the probability of receiving this virus through the email.

-Set B, that is the probability of receiving it through the webpage.

The most important information in these kind of problems is the intersection. That is, that he virus enters the system simultaneously by both email and webpage with a probability of 0.17. It means that $A \cap B$ = 0.17.

By email only

The problem states that there is a 40 chance of receiving it through the email. It means that we have the following equation:

$A + (A \cap B) = 0.40$

$A + 0.17 = 0.40$

$A = 0.23$

where A is the probability that the system receives the virus just through the email.

The problem states that there is a 40% chance of receiving it through the email. 23% just through email and 17% by both the email and the webpage.

By webpage only

There is a 35% chance of receiving it through the webpage. With this information, we have the following equation:

$B + (A \cap B) = 0.35$

$B + 0.17 = 0.35$

$B = 0.18$

where B is the probability that the system receives the virus just through the webpage.

The problem states that there is a 35% chance of receiving it through the webpage. 18% just through the webpage and 17% by both the email and the webpage.

What is the probability that the virus does not enter the system at all?

So, we have the following probabilities.

- The virus does not enter the system: P

- The virus enters the system just by email: 23% = 0.23

- The virus enters the system just by webpage: 18% = 0.18

- The virus enters the system both by email and by the webpage: 17% = 0.17.

The sum of the probabilities is 100% = 1. So:

P + 0.23 + 0.18 + 0.17 = 1

P = 1 - 0.58

P = 0.42

There is a probability of 42% that the virus does not enter the system at all.

5 0