Financial Calculations

1) Penalty Calculations

If there is delay in completion of work, as per work completion period in Tender according to conditions as below

Starting Penalty Amount = a

Increment in Penalty = d

Penalty Period = n

Then Total Penalty (T) can be calculated as

T = n/2 [2a + (n-1) d]

2) Simple Interest 

UPSC Prelims 2022 Q)The increase in the price of certain item was 25%. Then the price was decreased by 20% and then again increased by 10%. what is resultant increase in price?

Solution:- 

Lets assume price of item was 100

In crease in price = 25% so Price of item becomes =100+25 =125

Price was decreased by 20% = 125 *20/100 = 25, so New price = 125 -25 = 100

Price increased by 10% = 100 + 10 = 110

Resultant increase = 110-100 = 10

so answer is 10%