An Amplifier has a 50 watt output and a 5 watt input what is the gain in decibel?

Decibel gain is defines as 10 times the logarithm(base 10) of the ratio of output power to input power. So you have:


Gain(dB) = 10 \log_{10} (\frac {P_{out}}{P_{in}})


Here you have P_out = 50W and P_in = 5w. You asked this question in a Middle School forum - so I have to ask if you are familiar with logarithms?