A pencil costs $0.27 and a pen costs $0.32. You buy six pencils and the total cost is $4.18. How many pens did you buy?

2 Answers
Mar 25, 2018

#8# pens.

Explanation:

Let's model our situation with an equation.

We're going to have two variables, one for pencils and one for pens.

Let #p# stand for the number of pencils bought, #n# stand for the number of pens bought, and #C# be the total cost (in dollars):

#C=0.27p+0.32n#, as we're given the individual costs of pencils and pens.

We are given our cost, #C=$4.18#. Now, we're also told we buy #6# pencils, so #p=6.# Plug these into our equation:

#4.18=0.27(6)+0.32n#

What we're really being asked is to solve for #n,# so let's do that.

#4.18=1.62+0.32n#

#0.32n=4.18-1.62=2.56#

#n=2.56/0.32=8#

So, we bought #8# pens.

Mar 25, 2018

8 pens

Explanation:

say i bought #x# pencils and #y# pens
so #x# pencils cost #0.27 *x# dollars
similarly , #y# pens cost #0.32 * y# dollars

total cost = cost of x pencils +cost of y pens
4.18 = #0.27 * 6# + #0.32*y#
so #y = (4.18 -1.62)/0.32 =8 #

so i bought 8 pens