Tips to remember branch of study

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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N = the number of terms  .

S = the sum of the numbers in the set.

Average = S/N .


For example.

The marks of a student in five subjects are 96, 94, 92, 87, and 81, then what is the average score of the student?.

N = 5.

S = 96 + 94 + 92 + 87 + 81 = 450.

A = 450/5 = 90.


Another type questions .

1). There are 36 boys and 44 girls in a class. The average score of boys is 40 and girls are 35. Then what will be the average mark? .


Total mark of 36 boys = 36 x 40 = 1440.

Total mark of 44 girls = 35 x 44 = 1540.

Total mark of 80 Students = 1440 + 1540 = 2980 .

Average mark of the class = (2980 / 80).

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Suppose there are n people in the party. The first person shakes hand with the other (n-1) guests. The second guest shakes hand with the other (n-2) guests. this will continue until the (n-1) th guest shakes hand with the nth guest.

Total number of handshakes is (n-1) + (n-2).. + 3 + 2 + 1. .

= ((n-1)(n))/2 .

For example, 6 people in a party shake hand with other guests. So how many handshakes will be there?.

=((6-1)(6))/2.

=15.

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