Phrases/Financial

Cash Flows

   x=. 20 25 30 30             NB. payments
   y=. 0.05 0.05 0.06 0.06     NB. interest rates

NB. present value, payments start at end year
   +/ x % */\ 1+y
91.6116

NB. present value, payments start at beginning year
   +/ x % */\ 1, }: 1+y
96.6911

NB. future values, payments start at beginning year
    r * +/\ x % 1, }: r=. */\ 1+y
21 48.3 82.998 119.778

Rule of 78

   y=. 6                   NB. amortization period
   (% {.) |. +/\i. 1+y     NB. declining balances
1 0.714286 0.47619 0.285714 0.142857 0.047619 0

Work Done

Calculation of work done in periods given the capacity. Work exceeding capacity is carried forward to the next period.

   capacity=. 50 100 125 150 200
   demand=. 5$100
   capacity + 2 -/\ >./\ 0, +/\ capacity - demand
50 100 125 125 100

Internal Rate of Return

Internal rate of return for a project that requires initial investment of $90 and brings revenue $30, $40, $20 and $10 over next 4 years, after which terminates can be calculated as

   (#~1=*) %1{::p. _90 30 40 20 10
1.05202