document.write( "Question 840505: In 5 year's time, the sum of the ages ofna pair of twins and their elder sister is 45. The present age of the elder sister is 6 years less than the sum or the present age of the twins.Find the present ages of each twins and their elder sister \n" ); document.write( "
Algebra.Com's Answer #506217 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
In 5 year's time, the sum of the ages of a pair of twins and their elder sister is 45.
\n" ); document.write( " The present age of the elder sister is 6 years less than the sum or the present age of the twins.
\n" ); document.write( "Find the present ages of each twins and their elder sister
\n" ); document.write( ":
\n" ); document.write( "let s = elder sister's age
\n" ); document.write( "let t = age of the twins
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each statement, simplify as much as possible:
\n" ); document.write( ":
\n" ); document.write( "\"In 5 year's time, the sum of the ages of a pair of twins and their elder sister is 45.\"
\n" ); document.write( "s+5 + t+5 + t+5 = 45
\n" ); document.write( "s + 2t + 15 = 45
\n" ); document.write( "s + 2t = 45-15
\n" ); document.write( "s + 2t = 30
\n" ); document.write( ":
\n" ); document.write( "\"present age of the elder sister is 6 years less than the sum of the present age of the twins\"
\n" ); document.write( "s = 2t - 6
\n" ); document.write( ":
\n" ); document.write( "Replace s in the 1st equation with (2t-6)
\n" ); document.write( "(2t-6) + 2t = 30
\n" ); document.write( "2t + 2t = 30 + 6
\n" ); document.write( "4t = 36
\n" ); document.write( "t = 9 yrs old are the twins
\n" ); document.write( "then
\n" ); document.write( "s = 2(9) - 6
\n" ); document.write( "s = 18 - 6
\n" ); document.write( "s = 12 yrs is the age of the sister
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "See if that checks out in the 1st statement
\n" ); document.write( "\"In 5 year's time, the sum of the ages of a pair of twins and their elder sister is 45.\"
\n" ); document.write( "12 + 5 + 9 + 5 + 9 + 5 = 45
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "I'm not comfortable with the phrase \"a pair of twins\", we know twins are a pair, would a pair of twins be 4 people? Probably just poor writing. CK \n" ); document.write( "
\n" );