Question

A light bulb's brightness is reduced when placed behind a screen. The amount of visible light produced by the light bulb decreases by 25% with each additional layer that is added to the screen. With no screen, the light bulb produces 750 lumens. The lumen is a unit for measuring the total quantity of visible light emitted by a source. Select the correct equation that can be used to represent the lumens, L, after x screen layers are added.

Answer 1

Answer:

$L(x) = 750(0.75)^x$

Step-by-step explanation:

Equation for lumens, with x screen layers:

Has the following format:

$L(x) = L(0)(1-r)^x$

In which L(0) is the production with 0 layers and r is the decay rate for each additional layer.

Decreases by 25% with each additional layer that is added to the screen.

This means that $r = 0.25$

With no screen, the light bulb produces 750 lumens.

This means that $L(0) = 750$

Then

$L(x) = L(0)(1-r)^x$

$L(x) = 750(1-0.25)^x$

$L(x) = 750(0.75)^x$