document.write( "Question 402002: A is eleven times as old as B. In a certain number of years A will be five times as old as B, and five years after that she will be three times as old as B. How old are they now? \n" ); document.write( "
Algebra.Com's Answer #284421 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! Write an equation for each statement, simplify each equation: \n" ); document.write( ": \n" ); document.write( "\"A is eleven times as old as B.\" \n" ); document.write( "a = 11b \n" ); document.write( ": \n" ); document.write( "\"In a certain number of years A will be five times as old as B,\"; y = no. of yrs \n" ); document.write( "a + y = 5(b+y) \n" ); document.write( "a + y = 5b + 5y \n" ); document.write( "a = 5b + 5y - y \n" ); document.write( "a = 5b + 4y \n" ); document.write( "replace a with 11b \n" ); document.write( "11b = 5b + 4y \n" ); document.write( "11b - 5b = 4y \n" ); document.write( "6b = 4y \n" ); document.write( "6b - 4y = 0 \n" ); document.write( ": \n" ); document.write( "\"five years after that she will be three times as old as B.\" That's y+5 yrs \n" ); document.write( "a + y + 5 = 3(b + y + 5) \n" ); document.write( "a + y + 5 = 3b + 3y + 15 \n" ); document.write( "a = 3b + 3y - y + 15 - 5 \n" ); document.write( "a = 3b + 2y + 10 \n" ); document.write( "replace a with 11b \n" ); document.write( "11b = 3b + 2y + 10 \n" ); document.write( "11b - 3b = 2y + 10 \n" ); document.write( "8b = 2y + 10 \n" ); document.write( "8b - 2y = 10 \n" ); document.write( ": \n" ); document.write( "Multiply above equation by -2, add to the 1st equation \n" ); document.write( "-16b + 4y = -20 \n" ); document.write( " 6b - 4y = 0 \n" ); document.write( "----------------- \n" ); document.write( "-10b = -20 \n" ); document.write( "b = 2 yrs old \n" ); document.write( "Find a \n" ); document.write( "a = 11(2) \n" ); document.write( "a = 22 yrs old \n" ); document.write( ": \n" ); document.write( "We can say their present ages are: A=22; B=2 \n" ); document.write( ": \n" ); document.write( ": \n" ); document.write( "To check our our solutions, Find y \n" ); document.write( "6(2) - 4y = 0 \n" ); document.write( "12 - 4y = 0 \n" ); document.write( "-4y = -12 \n" ); document.write( "y = 3 yrs is that \"certain number of years\" \n" ); document.write( "; \n" ); document.write( "Check in the statement: \n" ); document.write( "\"In a certain number of years A will be five times as old as B, \n" ); document.write( "22 + 3 = 5(2 + 3) \n" ); document.write( "25 = 25 \n" ); document.write( ": \n" ); document.write( "You can check the solutions in the 3rd statement: \n" ); document.write( "\"five years after that she will be three times as old as B.\" That's y+5 yrs\"\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |