<prompt> Human: Imagine having 600,000 in the bank account.There is a house you want to buy that costs 400,000.Is it better to buy the house outright in cash?Or is it better to mortgage the house under a thirty year loan, and put all the extra money on mutual funds?  <response>: Not enough info. Two vital things are missing:- The interest rate- How much the buyer can expect to take advantage of the mortgage interest deduction i.e., whats their tax bracket, expected deductions... so how much they could save overall. 