Five times a number is 375. What is the number?

2 Answers
Apr 7, 2016

75.

Explanation:

So the first part of the question: "Five times a number is 375." is actually saying: "Some number multiplied by 5 is equal to 375", which looks like this:

#x*5= 375#

Which is the same as:

#5x= 375#

The second part of the problem: "What is the number?" tells us that they want us to solve for #x#. We can do this by dividing both sides of our equation (#5x= 375#) by 5, which looks like this:

#5x= 375#

=#(5x)/5= 375/5#

Lucky for us 375 is divisible by 5 (the divisibility rule for 5 states: any number is divisible by 5 if it ends in a 0 or 5) which means we will get a whole number as opposed to a fraction or decimal.

We can solve this with mental math if we remember that:

#5*20= 100#

and that:

#5*5=25#

If we add the 20 and the 5 together we get 25:

#20+5= 25#

Now if we multiply 25 by 5 we get 125 (This is the same as adding 100 and 25!). So this means that:

#5(20+5)= (100+25)#

This means that:

#5*25= 125#

125 just so happens to be 3 times smaller than our target number:

#375/125= 3#

This means that we can multiply 25 by 3 to solve for #x#.

#25*3= 75#

And there you have it! I hope that helped!

Jun 27, 2017

#75# is the number and see below for the procedure!

Explanation:

Well, using algebra for these kind of problems might save you more time than guessing! So let's start, shall we?

The formula: #x*5=375#
Now, lets leave #x# on one side and also get our answer by taking #5# to the other side. We are going to do that by dividing both sides by #5#! If you do something to one side, then you have to do it to the other! That will eliminate the #5# on left side and add 5 on the right side.

#x*5/ 5##=##375/5#

#x=375/5#
So our answer is #375/5#! Wait a second... oh yes, we have one more step to do in order to finish this equation! We have to simplify it! #5# can go into #375# so you can divide that!

#x=75#!

There, now we have our final answer!
My source is my mind!

-Moksha