Shortcut Tricks To Solve Percentage - 2

Shortcut Rules to Solve Problems on Percentage - 2

Effective for IBPS PO - SBI PO Exam

Dear Reader,

Here we will start a series of Quantitative Aptitude Shortcut Tricks for your upcoming SBI - IBPS - SSC and Other Government Competitive Exams. We will try to cover up all topics of the quantitative Aptitude Sections from which question was generally asked.

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Trick – 1

• If a number is successively increased by x%, y% and z%, then the single equivalent increases in that number will be

$\left[ x+y+z=\frac{xy+yz+zx}{100}+\frac{xyz}{{{100}^{2}}} \right]percent$ 

Trick - 2

• If one factor is increased by x% and the other increases by y%, then the effect on the product is given by 

$\left[ x+y+\frac{xy}{100} \right]percent$ increase.

Trick – 3

• If one factor is increased by x% and the other factor also increases by x%, then the effect on the product is given by

 $\left( 2x+\frac{{{x}^{2}}}{100} \right)percent$ increase.

Trick – 4

• A man spends x% of his income. His income is increased by y% and his expenditure also increases by z%, then the percentage increase in his savings is given by

$\left[ \frac{100y-xz}{100-x} \right]percent$

Trick – 5

• If the first value is r% less than the second value then, the second value is $\left[ \frac{r}{100-r}\times 100 \right]percent$ more than the first value.

Trick – 6

• If the annual decrease in the population of a town be r% and the present population be  then the population n years ago was $\frac{{{P}_{n}}}{{{\left( 1-\frac{r}{100} \right)}^{n}}}$ 

Questions for Practice

Q1. Find a single equivalent increase,  if a number is successively increased by 10%, 15% and 20%

Q2. The number of seats in a cinema hall is increased by 25%. The price of ticket is also increased by 10%. What is the effect on the revenue collected ?

Q3. The landholding of a person is increased by 10%. Due to early monsoon, the product increases by 10 %. Then, what is the effect on revenue ?

Q4. A man spends 75% of his income. His income is increased by 20% and his expenditure also increases by 10%. Find the percentage increase in his savings.

Q5. If A’s salary is 30% less than that of B, then how much percent is B’s salary more than that of A ? 

Q6. If the annual decrease in the population of a town be 4% and the present population be 57600, what was it 2 years ago ?

Answers

Answer 1. 51.8%

Answer 2. 37.5%

Answer 3. 21%

Answer 4. 50%

Answer 5. $42\frac{6}{7}%$ 

Answer 6. 62500