document.write( "Question 118675: This is a gre math problem....\r
\n" ); document.write( "\n" ); document.write( "a certain cake recipe states that the cake should be baked in a pan 8 inches in diameter. If Julie wants to use the recipe to make a cake of the same depth but 12 inches in diameter, by what factor should she muiltiply the ingredients?\r
\n" ); document.write( "\n" ); document.write( "my answer: 1.5 but this is wrong and statistics show that over 65% of the people taking the test got this wrong answer...\r
\n" ); document.write( "\n" ); document.write( "The correct answer is 2.25...why??? \r
\n" ); document.write( "\n" ); document.write( "If you can help, thanks!
\n" ); document.write( "

Algebra.Com's Answer #86802 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
Cake batter volume is the real variable that you're interested in here.
\n" ); document.write( "With a larger pan, you need more batter.
\n" ); document.write( "With a smaller pan, you need less batter.
\n" ); document.write( "For the same volume, you will have a definite relationship between the height and diamter.
\n" ); document.write( "The volume of the cake batter depends on the diameter of the pan and on the height of the pan.
\n" ); document.write( "For a cylindrical pan, the volume is
\n" ); document.write( "\"V=%28pi%29%2AD%5E2%2F4%2Ah\"
\n" ); document.write( "Originally let's use the subscript 1 to refer to 8 inch diameter pan.
\n" ); document.write( "\"V%5B1%5D=%28pi%29%2AD%5B1%5D%5E2%2F4%2Ah%5B1%5D\"
\n" ); document.write( "When it's a 12 inch diameter pan let's use subscript 2.
\n" ); document.write( "\"V%5B2%5D=%28pi%29%2AD%5B2%5D%5E2%2F4%2Ah%5B2%5D\"
\n" ); document.write( "Now let's plug in some numbers.
\n" ); document.write( "\"V%5B1%5D=%28pi%29%2A8%5E2%2F4%2Ah%5B1%5D\"
\n" ); document.write( "\"V%5B1%5D=%28pi%29%2A64%2F4%2Ah%5B1%5D\"
\n" ); document.write( "\"V%5B1%5D=16%2A%28pi%29%2Ah%5B1%5D\"
\n" ); document.write( "And for pan 2,
\n" ); document.write( "\"V%5B2%5D=%28pi%29%2AD%5B2%5D%5E2%2F4%2Ah%5B2%5D\"
\n" ); document.write( "\"V%5B2%5D=%28pi%29%2A12%5E2%2F4%2Ah%5B2%5D\"
\n" ); document.write( "\"V%5B2%5D=36%2A%28pi%29%2Ah%5B2%5D\"
\n" ); document.write( "Also, remember the depth is the same.
\n" ); document.write( "\"h%5B1%5D=h%5B2%5D=h\"
\n" ); document.write( "1.\"V%5B1%5D=16%2A%28pi%29%2Ah\"
\n" ); document.write( "2.\"V%5B2%5D=36%2A%28pi%29%2Ah\"
\n" ); document.write( "of re-writing the equation 2.
\n" ); document.write( "\"h=V%5B2%5D%2F%2836%2A%28pi%29%29\"
\n" ); document.write( "Now plug that value back into equation 1.
\n" ); document.write( "1.\"V%5B1%5D=16%2A%28pi%29%2Ah\"
\n" ); document.write( "\"V%5B1%5D=16%2A%28pi%29%2AV%5B2%5D%2F%2836%2A%28pi%29%29\"
\n" ); document.write( "\"V%5B2%5D=%2836%2F16%29%2AV%5B1%5D\"
\n" ); document.write( "\"V%5B2%5D=2.25%2AV%5B1%5D\"
\n" ); document.write( "So you need 2.25 times as much batter, so you multply all of the batter ingredients by 2.25.
\n" ); document.write( "
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