A pen costs twice as much as a pencil. If 7 pens and 12 pencils cost $6.50, find the cost of a pencil. I know the answer (pencil $0.25, pen $0.5), but I need to figure out how the answer is solved.

1. Observe the problem

2. Make a system of linear equations

x is pens

y is pencil

As stated in the text, x=2y

x=2y

7x+12y=6.50

Using substitution,

7(2y)+12y=6.50

14y+12y=6.50

26y=6.50

y=0.25

Substituting it back into the first equation:

x=2(0.25)

b

step-by-step explanation:

ez

3/4 ÷ 3/4

step-by-step explanation:

basically divide any proper fraction with itself to fit the criteria.

so if we are using 3/4, then:

3/4 ÷ 3/4 = 1

so 1 is the quotient.

and the numerators for both these fractions is 3.   and if we divide the numerators:

3 ÷ 3 = 1

we see that quotient is equal to our original quotient as well.