a) There was a 7.6 earthquake in Mindanao in the Philippines and a 5.7 aftershock three days later. Rounded to the nearest multiple of 10, how much stronger was the bigger quake?
b) An earthquake registering 5.7 is recorded one morning, and in the afternoon, another quake 27 times stronger is felt. Give the Richter reading of the second stronger quake. (Nearest tenth.)
c) What is the decibel reading of a sound that has 7 times more energy than a 75 decibel reading. (Nearest decibel.)
d) One singer is measured at 64 dB. Eight singers at the same level would have eight times more energy. To the nearest decibel, what is the decibel level of the eight singer chorus?
e) How much more energy is there in a reading of 75 dB compared to 64 dB. Round to the nearest whole number.
Answers in the comments.