SOLUTION: A grandmother wishes to save ₱150,000 for her granddaughters’ nursery education four years from now. How much should she deposit monthly in a bank if it pays at 6.5% conver

It is a classic Ordinary Annuity saving plan. The general formula is 


    FV = ,    


where  FV is the future value of the account;  P is the monthly payment (deposit); 
1+r is the monthly growth factor; n is the number of deposits (= the number of years multiplied by 12, in this case).


From this formula, you get for the monthly payment 


    P = .     (1)


Under the given conditions, FV = P150,000;  r = 0.065/12;  n = 4*12.  So, according to the formula (1), you get 
for the monthly payment 


    P =  = 2744.74.


Answer.  The necessary monthly deposit value is P2744.74.


Note that of projected  total  P150,000, the grandmother deposits only  4*12 times P2744.74, 
i.e. 4*12*2744.74 = P 131747.52. The rest is what the account earns/accumulates in 4 years.