6th Grade Algebra

[Roc]

Hi I am having problems with my 6th homework.. setting this up to solve it..

Here is the question
"Of the animals on a farm, 60% are cows and the rest are sheep. When 260 more cows and sheep are added to the farm, the percentage of cows increases by 20% and the number of sheep double. Find the number of sheep originally on the farm."

Thank you in Advance

 

[Quaid]

Denis, are you confusing the words "percent" and "percentage"?

I think that it's incomplete to say, "The percentage of cows = 72%"

Either of the following is clear.

"The number of cows = 72% of the animals"

"The percentage of cows = 72% of the animals"

Here, the phrases "number of cows" and "percentage of cows" are identical in meaning.

Given a number of animals, we calculate a percentage of that number by using the percent.

the problem should say: the percentage of cows increases to 72%

Well, the problem could have said, "The percentage of cows increases to 72% of the total animals".

But, then the exercise becomes easier. I think that the exercise statement is okay as posted.

Before adding 260 animals, there is an existing number of cows already on the farm. This original number of cows is the percentage of cows originally on the farm.

Where the exercise says, "...the percentage of cows increases by 20% ...", it means that the original number of cows increases by 20%. :cool:

 

[Quaid]

I am having problems ... setting this up

You tried something already, yes?

It's hard to help, when we don't know what you already understand about percents and percentages. Showing your work so far or explaining what you've thought about helps us provide direct assistance, often without the need for questions like below.

One way to begin is to assign a symbol to represent the unknown number of animals originally on the farm.

Let A = the number of animals originally on the farm

Once we determine the value of A, we can finish the exercise.

We're told that the original number of cows equals 60% of A.

Hopefully, you know how to write this percentage; it is 0.6A

In other words, the expression 0.6A represents the original number of cows.

Do you know how to increase 0.6A by 20%? That is, what expression can we write to represent the increased number of cows?

Two more questions to consider:

How do you express the original number of sheep, using symbol A?

If you double that amount, what is the new expression?


Answer these questions, and we will show you how to set-up an equation for finding A.

(Once you know A, the exercise answer is easily calculated.)

Cheers :cool: