Question 1184387


 

let the cost of the pen be {{{p}}} and the cost of the book {{{b}}}

if the total cost of a pen and a book is ${{{32}}}, we have

{{{p+b=32}}}.........eq.1

if the cost of the pen is {{{3/5}}} the cost of the book, we have

{{{p=(3/5)b}}}..........eq.2

substitute {{{p}}} in eq.1

{{{(3/5)b+b=32}}}.........eq.1

{{{(8/5)b=32}}}

{{{b=(32*5)/8}}}....simplify

{{{b=4*5}}}

{{{b=20}}}

then

{{{p=(3/5)20}}}
{{{p=(3/1)4}}}
{{{p=12}}}

the cost of the book is  ${{{20 }}}