Physics-WATT and LED question. Please help walk me through it:)

Question

An individual white LED (light-emitting diode) has an efficiency of 20% and uses 1.0 W of electric power.

1. How many LEDs must be combined into one light source to give a total of 1.6 W of visible-light output (comparable to the light output of a 40 W incandescent bulb)?
2. What total power is necessary to run this LED light source?

Answer 1

20% efficiency means that the LED received input of 1W, but puts out only 0.2 W of light.

1) So to get 1.6W of light we need

1.6/0.2 = 8 LEDs

2) These 8 LEDs will consume

8*1W = 8W