document.write( "Question 347403: a woman drove part of a 185 mi trip at 50 mi/h and the rest at 55 mi/h. Find the distance she traveled at 50 mi/h if her total driving was 3 hours and 30 min \n" ); document.write( "

Algebra.Com's Answer #248423 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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a woman drove part of a 185 mi trip at 50 mi/h and the rest at 55 mi/h.
\n" ); document.write( " Find the distance she traveled at 50 mi/h if her total driving was 3 hours and 30 min
\n" ); document.write( ":
\n" ); document.write( "Change 3 hr 30 min to 3.5 hrs
\n" ); document.write( ":
\n" ); document.write( "Let d = distance at 55 mph
\n" ); document.write( "then
\n" ); document.write( "(185-d) = distance at 50 mph
\n" ); document.write( ":
\n" ); document.write( "Write a time equation; time = dist/speed
\n" ); document.write( ":
\n" ); document.write( "Time at 55 mph + time at 50 mph = 3.5 hrs
\n" ); document.write( " $\"d%2F55\"$ + $\"%28%28185-d%29%29%2F50\"$ = 3.5
\n" ); document.write( ":
\n" ); document.write( "multiply by 550 to get rid of the denominators
\n" ); document.write( "10d + 11(185-d) = 550(3.5)
\n" ); document.write( "10d + 2035 - 11d = 1925
\n" ); document.write( "10d - 11d = 1925 - 2035
\n" ); document.write( "-1d = -110
\n" ); document.write( "d = 110 mi at 55 mph
\n" ); document.write( "then
\n" ); document.write( "185 - 110 = 75 mi at 50 mph
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check this by finding the actual times at each speed
\n" ); document.write( "110/55 = 2.0 hr
\n" ); document.write( "75/50 = 1.5 hr
\n" ); document.write( "------------------
\n" ); document.write( "total time 3.5 hrs \n" ); document.write( "

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