9 + n = x ?
i'm guessing since there's no answer to what the sum is
C is wrong...............
6 gives largest output and 12.7 or -.4 gives the smallest
70dB is represented by 100cars in 60sec. Therefore if the number of cats is reduced by 3/4 in the same amount of time(60s), then the decibel level will reduce by 3/4 also. So 70dB * .25= 17.5dB