document.write( "Question 88386: Please help me to solve the following equations: \r
\n" ); document.write( "\n" ); document.write( "Solve each formula for the indicated variable:\r
\n" ); document.write( "\n" ); document.write( "18) I= E/R+r for R\r
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\n" ); document.write( "\n" ); document.write( "Please find the value of the indicated variable:\r
\n" ); document.write( "\n" ); document.write( "Please show a complete solution to each problem. \r
\n" ); document.write( "\n" ); document.write( "36) Ride the peaks. Smith bicycled 45 miles going east from Durango, and Jones bicycled 70 miles. Jones averaged 5 miles per hour than smith, and his trip took one-half hour longer that Smith's. How fast was each one traveling?\r
\n" ); document.write( "\n" ); document.write( "Thank you so much for your assistance
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Algebra.Com's Answer #64193 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
solve each formula for the indicated variable:
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\n" ); document.write( "Assume you mean:
\n" ); document.write( "I = \"E%2F%28%28R%2Br%29%29\" for R
\n" ); document.write( ":
\n" ); document.write( "Multiply both sides by (R+r) and you have:
\n" ); document.write( "I(R+r) = E
\n" ); document.write( ":
\n" ); document.write( "Divide both sides by I and you have:
\n" ); document.write( "R + r = \"E%2FI\"
\n" ); document.write( ":
\n" ); document.write( "Subtract r from both sides:
\n" ); document.write( "R = \"%28E%2FI%29\" - r
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\n" ); document.write( ":
\n" ); document.write( "36) Ride the peaks. Smith bicycled 45 miles going east from Durango, and Jones bicycled 70 miles. Jones averaged 5 miles per hour than smith, and his trip took one-half hour longer that Smith's. How fast was each one traveling?
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\n" ); document.write( "Kind of a poorly worded problem, I interpret it to mean:
\n" ); document.write( "It took Jones a half hour longer to travel 70 mi than Smith to travel 45 mi
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\n" ); document.write( "Let s = smith's speed
\n" ); document.write( "then
\n" ); document.write( "(s+5) = Jone's speed
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\n" ); document.write( "Write a time equation;Time = Dist/time
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\n" ); document.write( "Smith's 45 mi time + half hr = Jone's 70 mi time
\n" ); document.write( "\"45%2Fs\" + \"1%2F2\" = \"70%2F%28%28s%2B5%29%29\"
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\n" ); document.write( "Multiply equation by 2s(s+5) to get rid of the denominators, we have:
\n" ); document.write( "45*2(s+5) + s(s+5) = 70*2s
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\n" ); document.write( "90s + 450 + s^2 + 5s = 140s
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\n" ); document.write( "s^2 + 90s + 5s - 140s + 450 = 0
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\n" ); document.write( "s^2 - 45s + 450 = 0; a quadratic equation
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\n" ); document.write( "Factors to:
\n" ); document.write( "(s - 15)(s - 30) = 0
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\n" ); document.write( "s = 15
\n" ); document.write( "and
\n" ); document.write( "s = 30
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\n" ); document.write( "Check both solutions
\n" ); document.write( "s = 15, then j = 20
\n" ); document.write( "45/15 = 3 hr
\n" ); document.write( "70/20 = 3.5 hr
\n" ); document.write( "and
\n" ); document.write( "s = 30, j = 35
\n" ); document.write( "45/30 = 1.5 hrs
\n" ); document.write( "70/35 = 2.0 hr
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\n" ); document.write( "Interesting that both solution work, isn't it?\r
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