Carlos pagó una cuenta de $300 con billetes de $5 y de $10. En total empleó 45 billetes para hacer el pago, ¿cuántos billetes de cada valor utilizó

30 billetes de 5 dólares y 15 billetes de 10 dólares

Step-by-step explanation:

I don't speak spanish but take it in school, so I understand the question but cannot respond back in spanish.

Letting x = $5 bills and y = $10 bills,

x + y = 45

5x + 10y = 300

Solving the system by substitution,

y = -x + 45

5x + 10(-x+45) = 300

5x - 10x + 450 = 300

-5x = -150

x = 30

Substituting the x-value back into the equation,

x + y = 45

30 + y = 45

y = 15

Checking my solutions, tells me that they are correct.

Hope this helped! If you don't understand the text, please us a translator!

9

step-by-step explanation: