Especially in the days before audio recording and playback, music was often written out as a means of preserving and communicating it. To do this, a system of notation was developed that gives musicians the information they need to play music as the composer intended it.
(Hope it helps :) )
About 73 years. You would use the compound interest formula.
1290=430 ( 1 + 1.5/100) ^ t
t = 73.788 years
The answer is C I think.... Wait yeah I just checked
