tu konvert 15 deg, Selseus tu Farenhite
yu need 2 thangs...1 is 1 deg Sel=1.8 deg F
2 is a kommon start point...sum yuze freez water=0 deg S & 32 deg F
sum yuze -40 deg=same number in both
15 deg S is 15 deg abuv freez, so F vershun=32+1.8*15
=32+27
=59