Faster Percentage Calculation

Formula :  .

Train Speed = Distance / Time.


Points to Remember .

To change km/hr into m/sec, we need to multiply it by 5 / 18. .

Example:.

90 km/hr means.

90 x 5 / 18.

= (5 x 5 ).

= 25 m/sec.

And if we need to convert m/sec into km/hr, we multiply it by 18 / 5.

Example:.

90 m/sec means.

90 x 18 / 5.

= ( 18 x 18 ).

= 324 km/hr.

Time taken by a train of length l meters to pass a pole or standing man or a signal post is equal to the time taken by the train to cover l meters.
Time taken by a train of length l meters to pass a stationary object of length b meters is the time taken by the train to cover (l + b) meters.
Suppose two trains or two objects bodies are mo...

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Important Maths Formulas .

(a ± b) 2 = a 2 ± 2ab + b 2 .


(a + b + c) 2 = a 2 + b 2 + c 2 + 2(ab + bc + ca).


(a + b + c + d) 2 = a 2 + b 2 + c 2 + d 2 + 2(ab + ac + ad + bc + bd + cd) .


Geometry formulas .

Perimeter ( ചുറ്റളവ് ) .


Perimeter of a square: P=4a.

    a: length of one side.


Perimeter of a rectangle: P=2(l+w).

    l: length.

    w: width.


Perimeter of a triangle: P=a+b+c.

    a, b, and c: lengths of the 3 sides.


Area ( വിസ്തീര്‍ണ്ണം ) .
LINE_FE...

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What is the divisibility by 2 Rule?.
Even numbers are multiples of 2. A number is even if ends in 0,2,4,6, or 8.
What is the divisibility by 3 rule?.
A number is divisible by 3 if the sum of its digits is divisible by 3.
372, for instance, is divisible by 3 since sum of its digits (3+7+2) is 12. And 12 is divisible by 3.
What is the divisibility by 4 rule?.
A number is divisible by 4 if the number\'s  last two digits are divisible by 4.
9,312, for instance, is divisible by 4 since its last 2 digits are 12. And 12 is divisible by 4.
What is the divisibility by 5 rule?.
A number is divisible by 5 if its last digit is a 0 or 5.
What is the divisibility by 6 rule?.
Since 6 is a multiple of 2 and 3, the rules for divisibility by 6 are a combination of the rule for 2 and the rule for   3.
Divisibility by 8 Rule.
A number passes the test for 8 if the las...

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