Question

An investor purchased 115 shares of stock,some at $3 per share and some at $2 per share. if the total cost was $270, them how many shares of each stock did the investor purchased?

Answer 1

Well we know the total number of shares he purchased of two stocks (stock x and stock y)
so we can write

x + y = 115

we also know that the total amount of money he spent on the two stocks is

$2x + $3y = $270

Answer 2

Solve for one variable in one of the equations (lets just say solve for x)

and then substitute that x value into the other equation. That will give you y which will tell you how many $3 shares he bought.

Then you can use your y answer and sub it into one of the equations and then solve for x, which will tell you how many $2 shares he bought