document.write( "Question 1185956: Three brothers shared a box of biscuits.
\n" );
document.write( "Roy ate of the box of biscuits and 1/3 of a biscuit.
\n" );
document.write( "Sam ate of the remaining biscuits and 1/3 of a biscuit.
\n" );
document.write( "Tom ate of the rest of the biscuits and 1/3 of a biscuit.
\n" );
document.write( "There were no biscuits left after this. How many biscuits did Roy a eat? \n" );
document.write( "
Algebra.Com's Answer #816830 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "When each brother eats 2/3 of the biscuits, 1/3 of them are left. So when each brother eats some of the biscuits, the number of biscuits remaining gets multiplied by 1/3 and the reduced by 1/3. So \n" ); document.write( "original number of biscuits: \n" ); document.write( "number after Roy eats his: \n" ); document.write( "number after Sam eats his: \n" ); document.write( "number after Tom eats his: \n" ); document.write( "The number of biscuits left at the end is 0, so \n" ); document.write( " \n" ); document.write( "That equation is actually not too hard to solve, although it is easy to get lost along the way.... \n" ); document.write( "This kind of problem is quite often easier to work backwards, especially if there are a large number of steps. (Imagine what the final equation above would look like if there had been five (or more) brothers.) \n" ); document.write( "At each step working the problem from beginning to end, the number of biscuits remaining is multiplied by 1/3 and then 1/3 is subtracted. Working that backwards, each step consists of adding 1/3 to the number remaining (the opposite of subtracting 1/3) and multiplying that by 3 (the opposite of dividing by 3). \n" ); document.write( "Working the problem backwards is then simple: \n" ); document.write( "biscuits remaining at the end: 0 \n" ); document.write( "biscuits remaining before Tom eats his: 3(0+1/3) = 3(1/3) = 1 \n" ); document.write( "biscuits remaining before Sam eats his: 3(1+1/3) = 3(4/3) = 4 \n" ); document.write( "biscuits remaining before Roy eats his: 3(4+1/3) = 3(13/3) = 13 \n" ); document.write( "There were 13 biscuits originally; Roy ate 9. \n" ); document.write( "ANSWER: Roy ate 9 biscuits \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |