document.write( "Question 124214: A TEST IS WORTH 150 PTS. THERE ARE 46 3 AND 5 PT QUESTIONS. HOW MANY OF EACH IS ON THE TEST? \n" ); document.write( "
Algebra.Com's Answer #91072 by edjones(8007)\"\" \"About 
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Let t be the number of 3 pt queations.
\n" ); document.write( "Let f be the number of 5 pt queations.
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\n" ); document.write( "t+f=46
\n" ); document.write( "3t+5f=150
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\n" ); document.write( "40 three point questions and 6 five pointers.
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Solved by pluggable solver: Linear Systems by Addition
We'll solve the system:
\n" ); document.write( " \"1%2At+%2B+1%2Af+=+46\"
\n" ); document.write( " \"3%2At+%2B+5%2Af+=+150\"
\n" ); document.write( " by elimination by addition.To eliminate by addition, we need to set both coefficients of x to numbers with changed signs, i.e a and -a. Since in the second equation we have 3 as our coefficient for x, to get -1 we have to multiply all terms of the second equation by \"-1%2F3\" which is equal to -0.333333333333333.
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\n" ); document.write( " Multiplying, we get on our second equation:\"%283%2A-0.333333333333333%29t+%2B+%285%2A-0.333333333333333%29f+=+150%2A-0.333333333333333\"
\n" ); document.write( " \"-1%2At+%2B+-1.66666666666667%2Af+=+-50\"
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\n" ); document.write( " Adding both equations we get:
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\n" ); document.write( " \"%281%2B-1%29t+%2B+%281%2B-1.66666666666667%29f+=+%2846%2B-50%29\"
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\n" ); document.write( " Since 1 and -1 cancel out, we have a linear equation:Therefore, we know that f = 6.
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\n" ); document.write( " Plugging that in into the first equation gives us:
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\n" ); document.write( " \"1%2At+%2B+1%2Af+=+46\"
\n" ); document.write( " \"1%2At+%2B+1%2A6+=+46\"
\n" ); document.write( " \"1%2At+%2B+6+=+46\"
\n" ); document.write( " \"1%2At+=+46+-+6\"
\n" ); document.write( " \"t+=+%2846+-+6%29%2F1\"
\n" ); document.write( " \"t+=+40%2F1\"
\n" ); document.write( " \"t+=+40\"
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\n" ); document.write( " Therefore, our answer is:
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\n" ); document.write( " \"system%28+t=40%2C+f=6+%29\"

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