document.write( "Question 855307: If 80 men dug 4 holes in 12 months, how many men would be required to dig 6 holes in 4 month? \n" ); document.write( "
Algebra.Com's Answer #515237 by Theo(13342)![]() ![]() You can put this solution on YOUR website! If 80 men dug 4 holes in 12 months, how many men would be required to dig 6 holes in 4 month?\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "80 men dug 4 holes in 12 months. \n" ); document.write( "divide that by 12 and you get 80 men dug 1/3 of a hole in 1 month. \n" ); document.write( "divide that by 80 and you get 1 man dug 1/240 of a hole in one month.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "does this make sense? \n" ); document.write( "let's see. \n" ); document.write( "1 man digs 1/240 of a hole in one month. \n" ); document.write( "working at the same rate, that same man can dig 12/240 of a hole in 12 months. \n" ); document.write( "80 men, working at the same rate per man, can dig (12 * 80) / 240 of a hole in 12 months.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(12 * 80) / 240 = 960 / 12 = 4, so: \n" ); document.write( "80 men, working at the same rate per man, can dig 4 holes in 12 months.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "formula makes sense, so we'll use it.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the formula can be condensed to:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "rate of work that each man produces * number of men * time = units of work produced.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this can be abbreviated to r * n * t = u \n" ); document.write( "r = rate of work that each man produces. \n" ); document.write( "n = number of men. \n" ); document.write( "t = time. \n" ); document.write( "u = units of work produced.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "time for this problem is in months. \n" ); document.write( "units of work produced are the holes in the ground.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we start with the first statement in the problem: \n" ); document.write( "80 men dug 4 holes in 12 months. \n" ); document.write( "the units of work produced is 4 holes \n" ); document.write( "the rate of work for each man is unknown so we'll keep it at r \n" ); document.write( "the number of men is given as 80. \n" ); document.write( "the time they took to do the work is given as 12 months.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the formula of r * n * t = u becomes: \n" ); document.write( "r * 80 * 12 = 4 \n" ); document.write( "solve for r to get: \n" ); document.write( "r = 4 / (80 * 12) = 4/960 = 1/240.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "so far we have:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "r = 1/240 \n" ); document.write( "n = 80 \n" ); document.write( "t = 12 \n" ); document.write( "u = 4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "to confirm we did this correctly, we check the original equation out with those numbers to see if the equation is true.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we get: \n" ); document.write( "r * n * t = u becomes: \n" ); document.write( "1/240 * 80 * 12 = 4 \n" ); document.write( "simplifying this equation, we get: \n" ); document.write( "240 = 240 which is true indicating we did this part of the problem correctly.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this part of the problem found the value of r which we will use in the next part of the problem.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we now look at the second part of the problem.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that part is the question: \n" ); document.write( "how many men would be required to dig 6 holes in 4 months.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the basic formula is the same. \n" ); document.write( "r * n * t = u \n" ); document.write( "r = 1/240 that we solved for earlier (the rate that each person works is assumed to be the same). \n" ); document.write( "n = n because we don't know what this is at the present time. \n" ); document.write( "t = 4 months \n" ); document.write( "u = 6 holes\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we plug these values into the equation to get: \n" ); document.write( "1/240 * n * 4 = 6\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we solve for n to get: \n" ); document.write( "n = 6 / (1/240 * 4) which becomes n = 6 / (4/240) which becomes n = 6 * 240/4 which becomes n = 6 * 60 which becomes 360.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "if we did this correctly, then it would take 360 men to fill 6 holes in 4 months.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "we confirm whether this is true or not by replacing n with 360 in the original equation to get: \n" ); document.write( "1/240 * n * 4 = 6 becomes: \n" ); document.write( "1/240 * 360 * 4 = 6 \n" ); document.write( "we simplify to get: \n" ); document.write( "6 = 6 confirming that our calculation of the number of people required is good.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the answer is that it would require 360 men to fill 6 holes in 4 months.\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |