### Home > INT3 > Chapter 8 > Lesson 8.3.2 > Problem 8-124

8-124.

Due to the worsened economy, merchants in downtown Hollywood cannot afford to replace their outdoor light bulbs when the bulbs burn out. On average, about 13% of the light bulbs burn out every month. Assuming there are now about one million outside store lights in Hollywood, how long will it take until there are only 100,000 bulbs lit? Until there is only one bulb lit? Homework Help ✎

The amount of lightbulbs is decreasing by a percentage, so this is an exponential decay problem.

If 13% are burning out, what percent remain? This is the multiplier.

For 100,000 bulbs lit, solve: 100,000 = 1,000,000(0.87)^{x}