If two light bulbs each use 50 watts and run for 4 hours, how many watts do they consume together?

To determine the total wattage consumed by the two light bulbs, first calculate the power consumption of each bulb. Since each bulb uses 50 watts, together they consume:

50 watts + 50 watts = 100 watts.

Next, to find the total energy consumed over a period of time, you multiply the total wattage by the number of hours they are used. In this case, the bulbs run for 4 hours:

100 watts × 4 hours = 400 watt-hours (Wh).

This value represents the total energy consumed by the two bulbs together over the specified time. Therefore, the correct answer is that they consume a total of 400 watts.