300,000+70,000+3,000+600+90+8
Answer:C
Explanation:
Power=280watts=280/1000 kilowatts
Power=0.28 kilowatts
Device use 0.28 kilowatts in 1 day
1day=24hours
Device use 0.28 kilowatts in 24hours
30days=30 x 24=720 hours
For 720 hours=(0.28x720) ➗ 24
For 720 hours=201.6 ➗ 24
For 720 hours=8.4
Its just Calcium Flouride because as you can see it is an Ionic bond (Ca is metal and fl is a gas usually)