Salim sells fax machines that come in Standard and Enhanced models. The Standard model sells for $325 and the Enhanced model sells for $385. If Salim sold a total of 35 units and took in $12,575, how many of the Enhanced model did he sell?

Let's assume that Salim sold 'x' units of the Enhanced model. Since he sold a total of 35 units, he must have sold (35 - x) units of the Standard model.

Now we can set up an equation based on the total sales revenue:

325(35 - x) + 385x = 12,575

To solve this equation, we can simplify it:

11,375 - 325x + 385x = 12,575

Combine like terms:

60x = 1,200

Divide both sides by 60:

x = 20

Therefore, Salim sold 20 units of the Enhanced model.

To find out how many of the Enhanced model Salim sold, let's assign variables to represent the unknowns. Let's say "S" represents the number of Standard models and "E" represents the number of Enhanced models.

We are given two pieces of information: the selling price of each model and the total units sold and total revenue generated.

From the given information:
- The Standard model sells for $325, so the revenue generated from selling Standard models is 325S.
- The Enhanced model sells for $385, so the revenue generated from selling Enhanced models is 385E.
- The total number of units sold is 35, so S + E = 35.
- The total revenue generated is $12,575, so 325S + 385E = 12,575.

Now we have a system of two equations:
S + E = 35
325S + 385E = 12,575

We can solve this system of equations using various methods, such as substitution or elimination.

Let's use the substitution method:
1. Solve the first equation for S: S = 35 - E.
2. Substitute this expression for S in the second equation: 325(35 - E) + 385E = 12,575.
3. Simplify and solve for E: 11,375 - 325E + 385E = 12,575.
Combine like terms: 60E = 12,575 - 11,375.
Simplify: 60E = 1,200.
Divide both sides by 60: E = 1,200 / 60 = 20.

Therefore, Salim sold 20 units of the Enhanced model.

number of standard models --- x

number of enhanced models --- 35-x

solve for x

325x + 385(35-x) = 12575

325x + 385(385 - x)= 12575

-325x + 13,475 - 385x = 12575
- 13,475 -325 = -13475

60x = 900
60x/60 = 900/60
x = 15