document.write( "Question 433642: a) A garrison has enough food to last for 24 days. How much longer will the food last if each individual ration can be reduced by 20 %?
\n" ); document.write( "b) By how much will each individual ration have to be reduced if the food is to last 40 days?
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Algebra.Com's Answer #300603 by rwm(914)\"\" \"About 
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Let F = the number of pounds in the total food supply.
\n" ); document.write( "The soldiers will use up the food in 24 days.\r
\n" ); document.write( "\n" ); document.write( "(a) Let x = amount of food (in pounds) each soldier eats per day.
\n" ); document.write( " In 24 days, they will eat 24x pounds of food, using up the F pounds of supply.
\n" ); document.write( "We have: 24x = F *\r
\n" ); document.write( "\n" ); document.write( "We reduce each soldier's ration by 20%,
\n" ); document.write( " then each soldier gets only 80% of his normal amount.
\n" ); document.write( "That is, each soldier eats 0.80x pounds of food per day.
\n" ); document.write( " And this will last N days.
\n" ); document.write( "We have: N(0.80x) = F **\r
\n" ); document.write( "\n" ); document.write( "Equate the two statements: N(0.80x) = 24x\r
\n" ); document.write( "\n" ); document.write( " Divide by x: 0.80x = 24\r
\n" ); document.write( "\n" ); document.write( "Divide by 0.80: x = 30\r
\n" ); document.write( "\n" ); document.write( " Therefore, the food will last 30 days, 6 days longer.\r
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\n" ); document.write( "\n" ); document.write( "(b) We want the food to last 40 days.\r
\n" ); document.write( "\n" ); document.write( "Each soldier will get a fraction of what he usually gets.
\n" ); document.write( " Call that fraction r.
\n" ); document.write( "Each soldier gets rx pounds of food per day.
\n" ); document.write( " In 40 days, they will eat: 40rx pounds of food.
\n" ); document.write( "In part (a), the total amount of food is 24x.\r
\n" ); document.write( "\n" ); document.write( "So we have: 40rx = 24x r = 24/40 = 3/5 = 60%\r
\n" ); document.write( "\n" ); document.write( "Each soldier will get only 60% of his normal ration.\r
\n" ); document.write( "\n" ); document.write( "Therefore, each ration is reduced by 40%.
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