Question

A shipment of computer monitors includes some that weigh 25 pounds and others that weigh 40 pounds each. The total weight of the shipment is 680 pounds. If there are 20 monitors in total, how many of them weigh 40 pounds?

a) 12
b) 14
c) 16
d) 8

Answer 1

To solve this problem, create a system of equations and use the elimination method to find the solution. There are 12 monitors that weigh 40 pounds.

Step-by-step explanation:

To solve this problem, we can create a system of equations. Let's assume that the number of monitors weighing 25 pounds is x, and the number of monitors weighing 40 pounds is y. According to the information given in the problem, we have the following system of equations:

x + y = 20 (Equation 1)

25x + 40y = 680 (Equation 2)

We can solve this system of equations using the substitution or elimination method. Let's use the elimination method in this case:

Multiplying Equation 1 by 25:

25x + 25y = 500 (Equation 3)

Subtracting Equation 3 from Equation 2:

25x + 40y - (25x + 25y) = 680 - 500

15y = 180

y = 12

Therefore, there are 12 monitors that weigh 40 pounds.