When the air temperature is a constant 70f, an object cools from 170f to 140f in one half-hour. what is the temperature of this object after 1 hour? equation: t(t)=ts+(to-ts)e^(-kt)

Agroup of five people go out to eat and buy appetizers and main dishes they decide to split the bill so each person pays 20% of the total cost appetizers are $5 and main dishes are $10 write an expression to show how much each person pays explain it with how to solve the problem