Feb 1 to Dec 15 is 10 1/2 months
in TWELVE months the account would earn 9.79% x 50,000 or .0979 x 50,000
the amount the account earns in only 10 1/2 months is a FRACTION of the amount in TWELVE months:
(10 1/2 ) / 12
Sooooooo the amount earned in 10 1/2 months is
(10 1/2) / 12 x .0979 x 50,000 = P 4283.125