Ben bought 7 notebooks for $34.50. some of the notebooks were $3.50 each and the others were $4.25 each. if x represents the number of least expensive notebooks, which equation can be used to find the number of least expensive notebooks purchased?

Given:

Total Price of 7 notebooks ben bought = $34.50

If X = number of least expensive notebook at $3.50, then

7-X=number of the other notebook at $4.25

The equation to find X will be:

X (3.50) + (7-X) 4.25=34.50

There are two types of notebooks which Ben bought. One type cost $ 3.50 each and the other type cost $4.25 each. The number of least expensive notebooks is x. This means Ben bought x notebooks of $ 3.50 each.

Since he bought 7 notebooks in total, the number of other notebooks will be

(7 - x)

The price of 7 notebooks was $34.50. So we can set up the equation as follows:

3.50x + 4.25 (7 - x) = 34.50

Using this equation we can find the value of x i. e. the number of least expensive notebooks purchased.