Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,632

**Simple Interest**

Simple Interest on P Dollars at interest rate r (expressed as a decimal) over time period t is

Example:- The Simple Interest on $400 for 3 months at 5% per annum Simpe interest would be

I=Prt

Hence Simple Interest on $400 for 3 months at 5% pa Simple Interest is 5 Dollars.

**Compound Interest**

The amount A, or future value, of principal P invested at interest rate r (expressed as decimal) compunded m times per year for t years is

where ,

the interest rate per compounding period, and n=mt, the number of compunding periods.

For example, Compound interest for $400 at the rate of 10% per annum compounded half yearly for 1 year would be calculated as follows:-

n=2 (1year = 2 half years).

i=10% pa = 5% per half year

Therefore, Compound Interest = $441-$400 = $41

**Annuity**

The future value of an Ordinary Annuity is

where R is the periodic payment, i the interest rate per period, and n the number of periods. In an ordinary annuity, the payment is made at the end of each period.

The present value of an ordinary annuity is

**Profit and Loss**

SP=Selling Price, CP=Cost Price

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**George,Y****Member**- Registered: 2006-03-12
- Posts: 1,330

What job can we do if you put all the tricks online ????

**X'(y-Xβ)=0**

Offline

**ganesh****Administrator**- Registered: 2005-06-28
- Posts: 25,632

**Discount**

If a discount x% is offered on price P, then

For example, if a discount of 15% is offered on a car worth $4000, then the discounted price is given by

**Successive Discounts**

If discounts of x% and y%, in that order succesively, are offered on price P, then

For example, if successive discounts of 10% and 20% are offered on an article worth $5000, then

It is no good to try to stop knowledge from going forward. Ignorance is never better than knowledge - Enrico Fermi.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

Offline

**john-penny****Member**- Registered: 2010-06-09
- Posts: 1

Offline