COMPETITIVE EDUCATION

Simple & Compound Interest Formulas and Tricks Simple Interest Formulas -   SI = p*t*r/100    The annual payment that will discharge a debt of INR A due in t years at the rate of interest r% per annum is =  (100 * A) / [(100 * t) + r*t* (t-1)]/2   P = (Interest * 100) / [(t1*r1) + (t2*r2) + (t3*r3) + …..]   Rate = [100 * (Multiple number of principal – 1)] / Time   Sum = (More Interest * 100) / (Time * More Rate) Compound Interest Formulas -   When Interest is compounded annually – Amount = P [1 + (r/100)] t   When Interest is compounded half-yearly – Amount = P [1 + (r/200)] 2t   When Interest is compounded quarterly – Amount = P [1 + (r/400)] 4t   When rate of Interest is r1%, r2% and r3% then – Amount = P [1 + (r1/100)] * [1 + (r2/100)] * [1 + (r3/100)]   Simple Interest for 2 years = 2*r = 2r% of capital   Compound Interest ...

Profit & Loss Formulas and Tricks   Profit = Selling Price (SP) – Cost Price (CP)       Loss = Cost Price (CP) – Selling Price (SP)   Gain or Loss % = (Loss or Gain / CP) * 100 %   Gain % = [Error / (True Value – Error)] * 100 %   Gain % = [(True Weight – False Weight) / False Weight] * 100 %   Total % Profit = [(% Profit + % Less in wt) / (100 – % Less in wt)] * 100 %   Cost Price = (More Gain * 100) / Diff in % Profit   Selling Price = [More Rupees * (100 + % Final Gain)] / (%gain + %loss)   Cost Price = [(Initial Profit%) + (Inc. in Profit%)] * A / (Inc. in Profit%)   If CP of x articles is = SP of y articles, then  Profit % =   [(x –y) / y] * 100   Cost Price = (100 * More Charge) / (% Diff in Profit)   Selling Price = More Charge * (100+ First Profit%) / (% Diff in Profit).

Percentage Formulas and Tricks   Percentage = [Value / Total Value * 100]       If two values are respectively x% and y% more than a third value, then the first is the  (100+x) / (100+y) *100%  of the second.   If A is x% of C and B is y% of C, then A is  x/y*100% of B .   x% of quantity is taken by the first, y% of the remaining is taken by the second and z% of the remaining is taken by third person. Now is A is left in the fund then there was ( A*100*100*100) / (100-x) (100-y) (100-z)  in the beginning.   x% of quantity is added. Again y% of increased quantity is added. Again z% of the increased quantity is added. Now, it becomes A, then the initial amount is given by (A*100*100*100) / (100+x) (100+y) (100+z)   If the original population of a town is P and the annual increase is r%, then the population in n years will be – P + P*r/100 = P*(1+r/100)   The population of a to...

Time, Distance & Work Formulas and Tricks  Time and Work Formulas -  If M1 persons can do W1 work in D1 days and M2 persons can do W2 work in D2 days, then the formula will be - M1 * D1 * W1 = M2 * D2 * W2  If we add Time for both the groups T1 and T2 respectively, then the formula will become – M1 * D1 * T1 * W1 = M2 * D2 * T2 * W2  And if we add efficiency for both the groups E1 and E2 respectively, then the formula becomes – M1 * D1 * T1 * E1 * W1 = M2 * D2 * T2 * E2 * W2  If A can do a piece of work in x days and B can do it in y days, then A and B working together will do the same work in  [(x*y)/(x+y)]  If A, B and C can do a work in x, y and z days respectively, then all of them working together can finish the work in  [(x*y*z) / (xy + yz + zx)]  If A and B together can do a piece of work in x days and A can do it in y days, then B alone can do the work in  (x*y) / (x-y)  Or...