TIME AND WORK

Time and work

Men days:

It is defined as the men multiplied by the day.

MxD= constant

Note:  If M1 men can do W1 work in D1 days H1 hours per day and M2 men can do W2 work in D2 days working H2 hours per day then

M1xD1xH1/W1=M2xD2xH2/W2

LCM AND HCF

LCM AND HCF

LCM: LCM is the least common multiple of two or more numbers is the smallest number that is divisible by each of these two given numbers.

HCF: HCM is the highest common multiple of two or more numbers is the largest number of the given numbers.

For example:

LCM of (3,6,9) is 18 and HCF of ( 3,6,9) is 3.

AREAS

AREAS OF RECTANGLE

A plan of a small garden is drawn to scale of 1 : 25. A pond covers 24cm2 on the plan. What is the area in m2 of the real pond.”

scale is given in length

so the area of pond will be A=24*(25)^2 cm^2

A=15000cm2

but 1m=100cm

so A=15000/(100*100)=1.5m^2

SIMPLE INTEREST AND COMPOUND INTEREST

SIMPLE INTEREST AND COMPOUND INTEREST

Principal:  The amount of money deposited or borrowed is called Principal.

Interest: The amount earned or paid for the use of money is called interest

SIMPLE INTEREST:  The interest that is earned only on the principal is called simple interst.

SI=(P*R*T)/100

where P=principal
R=rate of interest
T=time in year

Compound interest: The principal which is paid not ony pricipal but also on the interest is called compound interest.

The amount at the end of n years is given by

A=P(1+r/100)ⁿ

P=Principal

r=rate of interest

I=A-P