How much bituminous coal needs to be burned to obtain the same amount of energy as is released when burning 6 m3 gasoline?

Given:
q coal = 30,000,000 J / kg
q gasoline = 46,000,000 J / kg
V petrol = 6 m3
p (density) of gasoline = 710 kg / m3
To find:
m coal =?
Decision:
Q1 = Q2
Q1 = q petrol × m petrol
Q2 = q coal × m coal
q gasoline × m gasoline = q coal × m coal
m coal = (q gasoline × m gasoline) ÷ q coal
m coal = (710 × 6 × 46000000) ÷ 30000000 = 195960 ÷ 30 = 6532 kg
Answer: 6532 kg