During a sale at the bookstore, books sold for $3 and magazines sold for $2.50. jan spent $16 and bought a total of 6 books and magazines. how many of each did she buy

In the given question, there are several information's of immense importance. using these information's the required answer can be easily deduced. It is already given that Jan had spent $16 for buying books and magazines. The cost of each book is $3 and the cost of each magazine is $2.50. Jan bought a total of 6 books and magazines.
Let us assume  that the number of books Jan bought = x
the number of magazines Jan bought = y
Then
x + y = 6
x = 6 - y
and
3x + 2.5y = 16
Replacing the value of x from the first equation in the second we get
3x + 2.5y = 16
3(6 - y) + 2.5y = 16
18 - 3y + 2.5y = 16
- 0.5y = -2
y = 2/0.5
  = 4
Replacing the value of y in first equation we get
x + y = 6
x + 4 = 6
x = 2
So Jan bought 2 books and 4 magazines.