IBPS EXAMS, WWW.IBPSEXAMS.COM, IBPS Clerks, IBPS PO, IBPS RRB, Specialist Officers, SBI Jobs, Bank Jobs, IBPS Exam Materials, Short cuts, Exam Model papers, Results, Interview Tips, Latest Government Jobs, notification, recruitment, Results

PERCENTAGES SHORTCUTS FOR QUANTITATIVE APTITUDE

PERCENTAGES SHORTCUTS FOR QUANTITATIVE APTITUDE
1. " Percent " implies " for every hundred".
2.The base used for the sake of percentage change calculations is always the original quantity unless otherwise stated.
3. In general, if the percentage increase is p%, then the new value is [(p/100) +1]
4. If the new value is k times the old value, then the percentage increase is (k-1) x 100
Eg1: If the percentage increase is 300%, the new value is 4 times the old value.
If the new value is 4 times the old value, the percentage increase is 300%.
5. If there are successive increases of p%, q% and r% in three stages, the effective percentage increase is
= {[(100+p) /100] [(100+q)/100] [ (100+r)/100] -1} x 100
Eg2: The percentage increase in the value of exports of apples of a country is as follows:
2001- 2002 => 25 %; 2002-2003 => 20 %; 2003-2004 => 10%
What is the percentage increase in the value of exports of apples of the country from 2001 to 2004?
Ans : Let the value of exports in 2001 be 100 units.
Then total percentage increase is:
= {[(100+25)/100] [ (100+ 20)/ 100] [ (100+10)/100] - 1} x 100
= {(1.25) (1.20) (1.10) -1} x 100
= [1.65-1.00] x 100
= [0.65] x 100
= 65
________________________________________
6. If the price of an item goes up by x %, the percentage reduction required to bring it down to the original price is:
= {100x / (100+x)} %
Eg3: If the price of an item goes up by 10%, by what percentage should the new price be reduced to bring it down to the original price?
Ans: Percentage reduction = {100 x 10/ (100 + 10)} %
= (1000/110) %
= 9.09 %
________________________________________
7. If the price of an item goes down by x %, the percentage increase required to bring it back to the original price = {(100 x 10) / (100 - x)} %.
8. If A is x % more/ less than B, then B is {(100 x 10) / (100 - x)} % less/ more than A.
9. If the price of an item goes up by x %, then the quantity consumed should be reduced by {100x /(100 +x)} % so that the total expenditure remains the same.
10. If the price of an item goes downs by x %, then the quantity consumed should be increased by {100x /(100 -x)} % so that the total expenditure remains the same.
Eg4: If the price of tea goes up by 10%, then what should be the percentage decrease in the quantity consumed so that the total expenditure on tea remains the same?
Ans: Required Percentage decrease = { (10 x 100) / (100+10) }%
= (1000/110) %
= 9.09%

11. If A's income is x% more than that of B, then B's income is less than that of A by [(100r)/(100+r).
12. If B's income is x% less than that of A, then A's income is more that of B by [(100x)/(100-x)]
PERCENTAGES SHORTCUTS FOR QUANTITATIVE APTITUDE
1. " Percent " implies " for every hundred".
2.The base used for the sake of percentage change calculations is always the original quantity unless otherwise stated.
3. In general, if the percentage increase is p%, then the new value is [(p/100) +1]
4. If the new value is k times the old value, then the percentage increase is (k-1) x 100
Eg1: If the percentage increase is 300%, the new value is 4 times the old value.
If the new value is 4 times the old value, the percentage increase is 300%.
5. If there are successive increases of p%, q% and r% in three stages, the effective percentage increase is
= {[(100+p) /100] [(100+q)/100] [ (100+r)/100] -1} x 100
Eg2: The percentage increase in the value of exports of apples of a country is as follows:
2001- 2002 => 25 %; 2002-2003 => 20 %; 2003-2004 => 10%
What is the percentage increase in the value of exports of apples of the country from 2001 to 2004?
Ans : Let the value of exports in 2001 be 100 units.
Then total percentage increase is:
= {[(100+25)/100] [ (100+ 20)/ 100] [ (100+10)/100] - 1} x 100
= {(1.25) (1.20) (1.10) -1} x 100
= [1.65-1.00] x 100
= [0.65] x 100
= 65
________________________________________
6. If the price of an item goes up by x %, the percentage reduction required to bring it down to the original price is:
= {100x / (100+x)} %
Eg3: If the price of an item goes up by 10%, by what percentage should the new price be reduced to bring it down to the original price?
Ans: Percentage reduction = {100 x 10/ (100 + 10)} %
= (1000/110) %
= 9.09 %
________________________________________
7. If the price of an item goes down by x %, the percentage increase required to bring it back to the original price = {(100 x 10) / (100 - x)} %.
8. If A is x % more/ less than B, then B is {(100 x 10) / (100 - x)} % less/ more than A.
9. If the price of an item goes up by x %, then the quantity consumed should be reduced by {100x /(100 +x)} % so that the total expenditure remains the same.
10. If the price of an item goes downs by x %, then the quantity consumed should be increased by {100x /(100 -x)} % so that the total expenditure remains the same.
Eg4: If the price of tea goes up by 10%, then what should be the percentage decrease in the quantity consumed so that the total expenditure on tea remains the same?
Ans: Required Percentage decrease = { (10 x 100) / (100+10) }%
= (1000/110) %
= 9.09%

11. If A's income is x% more than that of B, then B's income is less than that of A by [(100r)/(100+r).
12. If B's income is x% less than that of A, then A's income is more that of B by [(100x)/(100-x)]

Share :

Facebook Twitter Google+
Back To Top