Tom wishes to purchase a property that's been valued at

$

$420$

$,$

$000$

$.$ He has

$15$

$\%$

of this amount available as a cash deposit and will require a mortgage for the remaining amount. The bank offers him a

$15$

$-$year mortgage at

$2\mathrm{.}5$

$\%$

interest. Calculate the total interest Tom will pay over the lifetime of the loan.