Mixture and Alligation Shortcut Methods
Formulae:
1. Average = sum of quantities/number of quantities
2. Sum = avg * no. of quantities
3. If the numbers are in A.P. (Arithmetic Progression), then the avg of numbers is given by
Avg = sum/n =[ (n/2)(a+l)]/n
= (a+l)/2
Where n – no. of quantities
a – first term or value
l – last term or value
4. Weighted Average:
Section1:
No. of quantities: m
Avg of section1: p
Section2:
No. of quantities: n
Avg of section1: q
Avg of section1 and section2 = (m*p + n*q)/(m +n)
Points to remember/Shortcuts
1. Average lies between minimum and maximum values.
a. Avg > minimum value
b. Avg < maximum value
2. If every quantity is increased/decreased by ‘k’ value, then the avg also get increased/decreased by the same ‘k’ value.
