At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
let x be no. of commer. of 30 sec and y be of 60 so x*30+y*60=11*60 and x+y=14 solve 2 equations
x = number of 30 second spots y = number of 60 second spots x + y = 14 30x + 60y = 660 11(60) = 660 seconds -30x - 30y = -420 30x + 60y = 660 30y = 240 y = 8 x + 8 = 14 x = 6 6 30 second spots 8 60 second spots
Thanks much I have a few more would you like more medals?
Don't care about the medals... but will help you... but we will work them together.
i will also help
Soybean meal is 12% protein; cornmeal is 6% protein. How many pounds of each should be mixed together in order to get 240 pounds mixture that is 9% protein?
First of all you should see we are talking about two different concepts (pounds and percents) we will start with pounds. x = pounds of soybean meal y = pounds of cornmeal OK so far?
OK.. what is the other number in the problem that deals with pounds and what do you think the equation is?
So what is the equation about pounds.
Good... now we need to deal with the percents.. There are three percents listed. 12%, 6%, and 9%
of the mixture 12% of it is soybean protein of the mixture 6% of it is cornmeal protein and we want to mix it to be 9% protein.
so .12x + .06y = .09(240) 12% of the soybean + 6% of the cornmeal will give you 240 pounds of 9% protein. OK
So we have 2 equations ... 2 variables. x + y = 240 .12x + .06y = .09(240)
x + y = 240 .12x + .06y = 21.60
I like to multiply every term by something to get rid of decimals... or multiplying means the same thing as moving the decimal. so I am going to move the decimal two to the right on every term... same thing as multiplying by 10
ok this is where I dnt understand really I have tried it this way and I dnt get anywhere but the wrong answer.....
x + y = 240 12x + 6y = 2160 OK so far? I will wait for your answer
OOPS same things as multiplying by 100 in the last post
well what happen to 9%?
I took the 9% times the 240 because at the end you want 240 pounds that is 9% protein. If you look above I had .09(240) which is 21.6
What do you mean by right? to what?
I will write what we have right now with every step so it is all together.
x + y = 240 .12x + .06y = .09(240) I am going to multiply .09 * 240 x + y = 240 .12x + .06y = 21.6 I am going to multiply each term by 100 x + y = 240 12x + 6y = 2160 Now is when we have to get rid of one of the letters. We can get rid of the x's or the y's. I am going to pick the y's because the 6 with the y is smaller than the 12 with the x.
The way we do that is to multiply one equation by some number that will get a variable that will cancel out so that we are only left with one variable. for example 6y - 6y = 0 another example -6y + 6y = 0 SO -6(x + y = 240) which when we distribute is -6x - 6y = -1440 OK???
Sorry I am not feeling good and I am trying to get these last few done so that I can go get some rest....
-6x - 6y = -1440 12x + 6y = 2160 Notice the y's are going to cancel out when we add 6x = 720 (I added the two equations together) x = 120 (I divided by 6) So if x = 120 and our first equation said x + y = 240 then 120 + y = 240 y = 120 so x = 120 and y = 120 120 pounds of soybeans and 120 pounds of cornmeal
ok gotcha I am trying to follow along sorry
that was easy 120 plus 120 then that would have been more simply
another one ?
A student makes a $9.75 purchase at the bookstore with a $20 bill. The store has no bills and give change in quarter and fifty cents pieces. There are 30 coins in all. How many of each kind are there?
Two concepts number of coins and money. x = number of quarters y = number of 50 cent pieces. So since we have 30 coins we have x + y = 30
Money wise we know that each quarter has a value of .25 so if you had 5 of them it would be worth .25 * 5 but in this problem we have x of them so the value is .25x same with the 50 cent pieces.. so .25x + .50y = 10.25 (we need the amount of change 20 - 9.75)
x + y = 30 .25x + .50y = 10.25 (multiply second equation by 100 to get rid of decimals) x + y = 30 25x + 50y = 1025 I am going to get rid of the x's by multiplying by -25 -25(x + y = 30) 25x + 50y = 1025 -25x - 25y = -750 25x + 50y = 1025 add the two equations. 25y = 275 (the x's canceled out) y = 11 so we had 11 50 cent pieces. Our first equation said x + y = 30 so x + 11 = 30 x = 19 so we had 19 quarters.
thanks very much.....rest time