Final answer:
To solve this problem, set up a system of equations using the number of small cups and large cups Diego sold. Solve the system using elimination or substitution to find the values of x and y. Diego sold 50 small cups and 25 large cups of lemonade.
Step-by-step explanation:
To solve this problem, we can set up a system of equations. Let's assume that Diego sold x small cups and y large cups. We can then set up the following two equations:
1x + 3y = 125 (equation 1)
x + y = 75 (equation 2)
We can solve this system of equations using either substitution or elimination. Let's use elimination. First, multiply equation 2 by -1:
-x - y = -75
Now, add equation 1 and -x - y:
1x - x + 3y - y = 125 - 75
Simplifying, we get:
2y = 50
Dividing both sides of the equation by 2, we find that y = 25. Now, substitute this value back into equation 2 to find x:
x + 25 = 75
Subtracting 25 from both sides, we get:
x = 50
Therefore, Diego sold 50 small cups and 25 large cups of lemonade.