1. Mr Suthan lives near a busy street. He has all the windows in his home open and measures the noise level inside as 80 dB. He closes the windows and finds the noise level is 68 dB. By what factor did the intensity of the noise decrease when Mr Suthan closed the windows?
+168 Percentage difference = (difference/original)x100
80-68= 12
(12/80)x100= -15% or by 0.85
