Maths Formula

1. income = expenditure + saving
2. if a,b is given number so third proportional to a and b is = b²/a
3. if a,b,c is given number so fourth propotional to a,b,c = (b⨯c)/a
4. simple interest (SI) = PRT / 100
5. area of walls = 2 h (l+b)      [h=height, l=length, b=breadth] unit in sq.m
6. speed = distance / time
7. speed of boatman = (speed of upstream + speed of downstream) / 2
8. average speed = total distance / total time
9. if some fraction are given so HCF of fractions = HCF of nemerators / LCM of denominators
10. profit = sp - cp     [cp=cost price, sp=selling price]
11. profit % = (profit / cp) ⨯ 100
12. area of trapezium = 1/2 ⨯ sum of parallel sides ⨯ height
13. volume of cylinder = πr²h
14. total surface area of cylinder = 2πr(r+h)
15. a^m ⨯ aⁿ = a^m+n
16. (x)^1/2 is same to √x  Example. (4)^1/2 = √4 = 2