PLEASE HELP ITS DUE IN 5 MIN PLEASE EXPLAIN HOW YOU GOT IT ALSO WILL MARK BRAINLEST

I'll give brainliest if you answer right : )

Subscriptions to a popular fashion magazine have gone down by a consistent percentage each year and can be modeled by the function y = 42,000(0.96)t. what does the value 42,000 represent in the function?

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?