<p>A farm has chickens that lay only white eggs and brown eggs. On a certain day, the chicken lay 750 eggs in which the ration of white eggs to brown eggs 7:3. If the ration of white eggs to brown eggs is to be chaged to 3:4 by adding only brown eggs, how many brown eggs must be added?</p>
<p>first you calculate the number of brown eggs and white eggs in the farm now, you get 525 white and 225 brown. then you will have to add x brown eggs to make the ration change to 3:4. this is to say, 525/(225+x)=3/4. x=475
you must add 475 brown eggs:)!</p>
<p>7/3 = (750 -x)/x</p>
<p>7x = 2250 - 3x
10x = 2250
x = 225 brown eggs</p>
<p>525/(225 + x) = (3/4)</p>
<p>2100 = 675 + 3x
1425 = 3x
x = 475 brown eggs</p>
<p>an easy trick to ratios and finding the actual amount is:</p>
<p>add the ratio and divide by the total, so since it is 7:3, 7+3=10. 750/10=75. take that number and multiply it by the ratios and that is the answer. 7:3, 7x75=525, 3x75=225.
hope it helps</p>
<p>Thank you dk333, It really does help. :)
Does that question come from the Princeton Review 11 Practice SATs and PSAT book? ;)</p>
<p>yessssssir</p>
<p>x= white eggs
y= brown eggs</p>
<p>.7x + .3y= 750
x= 525
y= 225</p>
<p>then, 525/225 + y= 3/4
y= 475</p>
<p>I JUST DID THIS QUESTION! </p>
<p>Was it in the Princeton REview 11 Tests book? ... I believe that's the book I was studying out of..</p>
<p>But yea it took me a minute to figure out... but i got it! :-)</p>
<p>Just did this question as well, about 2 days ago. Wasn't hard at all, but it seems like something that would definitely show up on the sat as one of the harder (end of the section) questions.</p>