please help answer the question below

The difference in sound levels, in decibels, can be found sing the equation g B1 = 10 log (if) , where I1 and [2 are the intensities of the two sounds, in watts per square meter. If a power mower makes'la noise that is measured at 109 dB and ordinary traffic registers at about 71 dB, how many times louder is the mower than the traffic? Round your answer to the nearest whole number