MyMaths MyLife

I am a big fan of cricket, i rate cricketers on the basis of their averages. Average is nothing but consistency.

Average is very simple but effective way of representing an entire group by a single value.

Average of any number of quantities will always be higher than the lowest value and lower than the highest value of items whose average is being taken.

1.Average = Sum of quantities/Number of quantities.

2.Suppose a man covers a certain distance at x kmph and an equal distance at y kmph,then the average speed during the whole journey is (2xy/x+y) kmph.

Sometimes it so happens that the borrower and the lender agree to fix up a certain unit of time ,say yearly or half-yearly or quarterly to settle the previous account.
In such cases ,the amount after the first unit of time becomes the principal for the 2nd unit ,the amount after second unit becomes the principal for the 3rd unit and so
on. After a specified period ,the difference between the amount and the money borrowed is called Compound Interest for that period.

Formulae:
As we discussed in the simple interest
Let principal=p,Rate=R% per annum Time=nyears

1.When interest is compounded Annually, Amount=P[1+(R/100)]n
2.When interest is compounded Half-yearly, Amount=P[1+((R/2)100)]2n
3.When interest is compounded Quarterly, Amount=P[1+((R/4)100)]4n
4.When interest is compounded Annually,but time in fractions
say 3 2/5 yrs Amount=P[1+(R/100)]3[1+((2R/5)/100)]
5.When rates are different for different years R1%,R2%,R3%
for 1st ,2nd ,3rd yrs respectively Amount=P[1+(R1/100)][1+(R2/100)][1+(R3/100)]
6.Present Worth of Rs.X due n years hence is given by
Present Worth=X/[1+(R/100)]n

When you borrow money from some one he will give you money for interest. Usually money lender calculates simple interest and gives you money.

The interest is calculated only on the principal through out the loan period, it is called simple interest.

Principal or Sum:- The money borrowed or lent out for a certain period is called Principal or the Sum.

Interest:- Extra money paid for using others money is called Interest.

Simple Interest:- If the interest on a sum borrowed for a certain period is reckoned uniformly,then it is called Simple Interest.

Formulae:
Principal = P
Rate = R% per year
Time = T years. Then,

(i)Simple Interest(S.I)= (P*T*R)/100

(ii) Principal(P) = (100*S.I)/(R*T)
Rate(R) = (100*S.I)/(P*T)
Time(T) = (100*S.I)/(P*R)