Average calculation
Average calculationN = 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)
= 37.25
2). The average weight of 15 members in a football team is 24 kg when a new member included, the average weight increases by 2. What is the weight of the new member?
Total weight of 15 member = 24 x 15 = 360
Average after including a new member = 24 + 2 = 26
Total weight of 16 member = 26 x 16 = 416
Weight of the new member = Total weight of 16 member - Total weight of 15 member
= 416 - 360
= 56.
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...
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...
P - Principal, the sum of money lent or borrowed. .
R - Rate of interest: Annual interest, often expressed as a percentage. .
T - Time period for which the money is lent or borrowed. .
Simple Interest = Principal * Time * Rate of interest / 100 .
SI = 4000× 8% × 4 = 4000× 0.08 × 4.
= 1280. .
In compound interest , the principal amount with interest after the first time period becomes the part of principal for the next time period.
CI = [P (1 + R/100)^T] – P .
Total amount = [P (1 + R/100)^T] .
If time period is half-yearly, .
Amount = P[1 + (R/2)/100]^2T .
If time period is quarterly, .
Amount = P[1 + (R/4)/100...
















