document.write( "Question 1166743: A lady traveled 100 kilometers at a rate of 30 kilometers an hour. If she wants her return trip to be three-fourths of her trip, at what rate must she return? \n" ); document.write( "
Algebra.Com's Answer #791259 by Theo(13342) You can put this solution on YOUR website! r*t=d \n" ); document.write( "r = rate \n" ); document.write( "t = time \n" ); document.write( "d = distance\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the lady traveled 100 kilometers at a rate of 30 kilometers per hour. \n" ); document.write( "the formula for her becomes 30 * t = 100 \n" ); document.write( "solve for t to get t = 100 / 30 = 10/3 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "she wants her return trip to take 3/4 of the time it took her to get to her destination.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3/4 * t = 3/4 * 10/3 = 30/12 = 10/4.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "instead of taking 10/3 hours, the trip back should take 10/4 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the formula of r * t = d becomes: \n" ); document.write( "r * 10/4 = 100 \n" ); document.write( "solve for r to get: \n" ); document.write( "r = 400/10 = 40\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "going there she travels at 30 kilometers per hour. \n" ); document.write( "coming back she travels at 40 kilometers per hour.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the formula for going there is 30 * t = 100 \n" ); document.write( "the formula for coming back is 40 * t = 100\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the time for going there is 100 / 30 hours. \n" ); document.write( "the time for coming back is 100 / 40 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3/4 * 100 / 30 is equal to 300 / 120 which is equal to 100 / 40. \n" ); document.write( "that's the time it takes to get back, confirming the solution is correct.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the solution is that she must comes back at the rate of 40 kilometers per hour.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "i worked in fractions because the decimals were repeating. \n" ); document.write( "you can work in decimals as well as long as you round to enough decimal digits so that the repeating decimals will still give you the correct answer.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "for example, i did the following:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "r * t = d becomes 30 * t = 100 when she is going to her destination. \n" ); document.write( "solve for t to get t = 100/30 = 3.33333 rounded to 5 decimal places. \n" ); document.write( "she wants t on the return trip to be equal to 3/4 of the time going. \n" ); document.write( "3/4 * t = 3/4 * 3.33333 = 2.5 \n" ); document.write( "the formula of r * t on the return trip becomes r * 2.5 = 100 \n" ); document.write( "solve for r to get r = 100 / 2.5 = 40 hours.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "working in decimal wasn't as bad as i thought. \n" ); document.write( "either way, you get the same answer. \n" ); document.write( "the answer is 40 kilometers per hour.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solution is that she would have to travel back at 40 kilometers per hour so that the time required on the return trip is 3/4 of the time taken getting to her destination.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |