document.write( "Question 74258: can you help me in solving the problem...\r
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document.write( "ariana took 2 h longer to drive 360 mi on the first day of a trip than she took to drive 270 mi on the second day. if her speed was the same on both days, what was the driving time each day? \n" );
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Algebra.Com's Answer #53263 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! We're going to use the equation that says Distance (D) is equal to the Rate (R) times the Time (T) \n" ); document.write( "or in equation form: \n" ); document.write( ". \n" ); document.write( "D = R*T \n" ); document.write( ". \n" ); document.write( "On the second day she drove 270 miles in the time T. In equation form this is: \n" ); document.write( ". \n" ); document.write( "270 = R*T \n" ); document.write( ". \n" ); document.write( "Solve this equation for R by dividing both sides by T to get R = 270/T \n" ); document.write( ". \n" ); document.write( "On the first day she drove 360 miles in the time T+2. In equation form this is: \n" ); document.write( ". \n" ); document.write( "360 = R*(T+2) \n" ); document.write( ". \n" ); document.write( "Solve this equation for R by dividing both sides by (T+2) to get R = 360/(T+2) \n" ); document.write( ". \n" ); document.write( "The problem then says the R is the same on both days. Since it equals 360/(T+2) on the \n" ); document.write( "first day and 270/T on the second day we can set these two equal to get: \n" ); document.write( ". \n" ); document.write( "360/(T+2) = 270/T \n" ); document.write( ". \n" ); document.write( "Multiply both sides by (T+2) to get rid of the denominator on the left side and you get: \n" ); document.write( ". \n" ); document.write( "360 = 270*(T+2)/T \n" ); document.write( ". \n" ); document.write( "Then multiply both sides by T to get rid of the denominator on the right side. The equation becomes: \n" ); document.write( ". \n" ); document.write( "360T = 270*(T+2) \n" ); document.write( ". \n" ); document.write( "Multiply out the right side and the equation further becomes: \n" ); document.write( ". \n" ); document.write( "360T = 270T + 540 \n" ); document.write( ". \n" ); document.write( "Next get rid of the 270T on the right side by subtracting 270 from both sides of the equation: \n" ); document.write( ". \n" ); document.write( "90T = 540 \n" ); document.write( ". \n" ); document.write( "Now you can solve for T by dividing both sides of the equation by 90 and the result is: \n" ); document.write( ". \n" ); document.write( "T = 540/90 = 6 \n" ); document.write( ". \n" ); document.write( "So the time (T) which is the driving time on the second day is 6 hours. That means that \n" ); document.write( "on the first day she drove 2 additional hours for a total driving time on the first day \n" ); document.write( "of 8 hours. \n" ); document.write( ". \n" ); document.write( "Another and quicker way you could have done this problem is to say that that on the first \n" ); document.write( "day she spent 2 more hours on the road and she drove 90 more miles (360 miles on that day \n" ); document.write( "and 270 miles on the second day). So in those 2 hours she averaged 45 miles per hour to cover \n" ); document.write( "those 90 miles in 2 hours. So at 45 miles per hour it would take 8 hours to cover the \n" ); document.write( "360 miles. On the second day she still drove at 45 mph and to cover 270 miles divide 270 by 45 \n" ); document.write( "and find that it took 6 hours. \n" ); document.write( ". \n" ); document.write( "Hope these two approaches to solving the problem give you some insight into the relationship \n" ); document.write( "among distance, rate, and time. \n" ); document.write( " \n" ); document.write( " |