Question 1122914



let’s Sara’s age be {{{s}}}, Fiona’s age {{{f}}}, and Paul’s age {{{p}}}

given: 
Sara is {{{3}}} years older than Fiona, =>{{{s=f+3}}}....eq.1
Paul is {{{3}}} years younger than Fiona, =>{{{p=f-3}}}....eq.2

 the total of their ages is {{{60}}},=>{{{s+f+p=60}}}....eq.3

substitute {{{s}}} and {{{p}}} from eq.1 and eq.2 into eq.3

{{{f+3+f+f-3=60}}}

{{{3f=60}}}

{{{f=60/3}}}

{{{f=20}}}->Fiona is {{{20}}} years old

go to
{{{s=f+3}}}....eq.1..substitute {{{f}}}

{{{s=20+3}}}

{{{s=23}}}-> Sara  is {{{23}}} years old

go to
{{{p=f-3}}} ....eq.2..substitute {{{f}}}

{{{p=20-3}}}

{{{p=17}}} ->Paul is {{{17}}} years old


so,  the youngest of them is {{{17}}} years old