Question 300769
Let W be the price of writing tablets, P be the price of pens.
1.{{{7W+4P=6.40}}}
2.{{{2W+19P=5.40}}}
Multiply eq.1 by 2 and eq. 2 by (-7) and add them together to get rid of W.
{{{(14W+8P)+(-14W-133P)=12.80-37.80}}}
{{{125P=25}}}
{{{P=0.2}}}
Then use either equation to solve for W.
{{{7W+4P=6.40}}}
{{{7W+4(0.2)=6.40}}}
{{{7W+0.80=6.40}}}
{{{7W=5.60}}}
{{{W=0.80}}}
Writing tablets are $0.80 and pens are $0.20.