document.write( "Question 771479: Simultaneous equation
\n" ); document.write( "Exercise 7: solving problem using simultaneous equation
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\n" ); document.write( "Jacob travels from A to B, a distance of 410 km over 9 hours. Some of the time (say x hours) Jacob travelled at a speed of 50 km/h, and for the rest of time (say y hours) he travelled at 40 km/h.
\n" ); document.write( "Find the number of hours he traveled at 40 km/h.
\n" ); document.write( "Please help and solve my problem. I need your solving and the answer. Please. I got stuck in 2 days ago. \n" ); document.write( "
Algebra.Com's Answer #470254 by ramkikk66(644)\"\" \"About 
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document.write( "Jacob travels from A to B, a distance of 410 km over 9 hours. Some of the time (say x hours) Jacob travelled at a speed of 50 km/h, and for the rest of time (say y hours) he travelled at 40 km/h.\r\n" );
document.write( "Find the number of hours he traveled at 40 km/h.\r\n" );
document.write( "Ans:\r\n" );
document.write( "If he travelled for x hours at 50 kmph and y hours at 40 kmph, we have 2 equations\r\n" );
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document.write( "x + y = 9 -----> (1) since total time is 9 hours\r\n" );
document.write( "50*x + 40*y = 410 -----> (2) since total distance is 410 km\r\n" );
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document.write( "One way of solving the above is by elimination.\r\n" );
document.write( "If the coefficients of either x or y is the same in both the eqns, we can\r\n" );
document.write( "subtract one from the other to eliminate x or y and solve for the other\r\n" );
document.write( "variable.\r\n" );
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document.write( "Multiply eqn (1) by 40 to make the coefficient of y also as 40. We get\r\n" );
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document.write( "40*x + 40*y = 360 -------> (3)\r\n" );
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document.write( "Subtract eqn (3) from eqn (1)\r\n" );
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document.write( "(50*x - 40*x) + (40*y - 40*y) = 410 - 360 = 50\r\n" );
document.write( "10*x = 50\r\n" );
document.write( "x = 5\r\n" );
document.write( "Since x + y = 9, y = 4\r\n" );
document.write( "So he travelled for 5 hours at 50 kmph, and 4 hours at 40 kmph\r\n" );
document.write( "Check for correctness:\r\n" );
document.write( "Total distance travelled = 5*50 + 4*40 = 250 + 160 = 410. Correct.\r\n" );
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