How do you write n over 3 -5 in a word phrase

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years

Stefanie is painting her bedroom. she can paint 2 1/3 square feet in 4/5 of an hour. how many square feet can she paint in one hour?

The graph shows the decibel measure for sounds depending on how many times as intense they are as the threshold of sound. noise in a quiet room is 500 times as intense as the threshold of sound. what is the decibel measurement for the quiet room? 20 decibels28 decibels200 decibels280 decibels