Question 682258


let {{{x}}} be anna's and {{{y}}} jeff's age 

given:

anna is one year younger; means

{{{x+1=y}}}.............1

the sum of anna's and jeff's age is {{{23}}}, means

{{{x+y=23}}}.......substitute {{{y}}} from 1

{{{x+x+1=23}}}....solve for {{{x}}}

{{{2x+1=23}}}

{{{2x=23-1}}}

{{{2x=22}}}

{{{x=11}}}.........anna's age

so, if {{{x+1=y}}} 

{{{11+1=y}}}

{{{12=y}}}........jeff's age

check the product:

the product is {{{132}}}

{{{11*12=132}}}

{{{132=132}}}