Mark invests $2,243 in a retirement account with a fixed annual interest rate of 3% compounded continuously. What will the account balance be after 15 years?

You start by multiplying 2,243 times 0.03(The representation of 3% as a decimal)
After you get 67.29, you multiply that by 15.
So the answer is $1009.35 in interest rate in 15 years

The enviroment with hedge hogs

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen