Formula Technique 10 & 11

Formula Technique 10: Compound Interest Calculation

Compound interest simply means interest on ‘interest + initial amount’. In this case once interest is earned on a certain amount and then consequent amount is re invested as new amount at the same rate of interest.

Relations used for calculation of compound interest are;

And

From first relation we calculate ‘A’ i-e the amount after investing initial amount ‘P’ at the rate of interest ‘R’  for time term ‘T’- and once ‘A’ is found , then  from second relation we can find interest ‘I’ , which is the compound interest.

Example: Calculate interest on $5000 for two years at rate of 10 % per year compound yearly Solution: Here P=5000$

R=10

T= 2 years

I = ?

Putting values in first relation i-e

We get,

But

So, the compound interest is 1050 \$

Formula Technique 11: Liquid Flow Out and In a Container

Suppose we have a drum in which some liquid is being filled via a tap, and at the same time the liquid is being taken out via another tap at fixed at the bottom,

Then,

Filling rate = input rate – out put rate i-e filling rate of the container will be estimated by taking difference of inflow rate and out flow rate

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Insert math as
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