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

88 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 pp stand for the number of pencils bought, nn stand for the number of pens bought, and CC be the total cost (in dollars):

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

We are given our cost, C=$4.18C=$4.18. Now, we're also told we buy 66 pencils, so p=6.p=6. Plug these into our equation:

4.18=0.27(6)+0.32n4.18=0.27(6)+0.32n

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

4.18=1.62+0.32n4.18=1.62+0.32n

0.32n=4.18-1.62=2.560.32n=4.181.62=2.56

n=2.56/0.32=8n=2.560.32=8

So, we bought 88 pens.

Mar 25, 2018

8 pens

Explanation:

say i bought xx pencils and yy pens
so xx pencils cost 0.27 *x0.27x dollars
similarly , yy pens cost 0.32 * y0.32y dollars

total cost = cost of x pencils +cost of y pens
4.18 = 0.27 * 60.276 + 0.32*y0.32y
so y = (4.18 -1.62)/0.32 =8 y=4.181.620.32=8

so i bought 8 pens