Question

Jonathan collects postcards and stamps. The number of postcards in his collection is 12 more than 3/4 the number of stamps. He has 39 postcards in all. If Jonathan has x stamps, which equation represents this situation and how many stamps does he have?

Answer 1

For this case we define the following variable:

• x: number of stamps

We now write the equation that models the problem:

$\frac {3} {4} x + 12 = 39$

From here, we clear the value of x.

We have then:

$\frac {3} {4} x = 39-12\\\frac {3} {4} x = 27\\x = (\frac {4} {3}) (27)\\x = (4) (9)\\x = 36$

Answer:

The number of stamps he has is:

$x = 36$

Answer 2

12 + (3/4x) = 39

3/4x = 39 - 12

(4/3)(3/4)x = 27 (4/3)

x = 36

He has 36 stamps.

Hope this helps!