Question 726300


The cost of {{{4}}} notebooks and {{{5}}} pens is ${{{20}}}. 

 if the cost of a notebook "{{{n}}}" and the cost of a pen "{{{p}}}", than you have
{{{4n+5p=20}}}.....eq.1 


and, if he cost of {{{6}}} notebooks and {{{2}}} pens is ${{{19}}}, than you have

{{{6n+2p=19}}}.....eq.2 

so, system of equations can be used to find the cost of a notebook "n" and the cost of a pen "p" is:

{{{4n+5p=20}}}.....eq.1 
{{{6n+2p=19}}}.....eq.2 
______________________________

so, your answer is

B)
{{{4n + 5p = 20}}} and {{{6n + 2p = 19}}}