Tuesday, 16 May 2017

Simplification IV – Root Digit Method for Simplification Questions in IBPS PO Exam

In this post, we will discuss how to solve simplification questions for IBPS PO Exam using root digit method in less time
Simplification Questions in Bank Exams

Simplification questions are the most complex and time taking questions in IBPS PO Exam. Solving them using regular method is a very tedious job. So to break the complex process and help you solve these simplification questions for bank exams, we will discuss root digit method which is simple and takes less time.

In our previous posts- Simplification I - Simplification Tricks to Solve Simplification Problems, Simplification II - Simplification Questions for IBPS PO Exam and Simplification III – Simplification Questions solved using Unit Digit Method we have discussed few simplification questions for bank exams based on unit digit method and have solved few simplification questions using simplification tricks. In this post, we will discuss Root Digit Method and solve few simplification questions for bank exams.

Root Digit Method
Remember, when we go for vehicle registration, we add up all the numbers till we get a single digit to figure out whether the number is lucky or not? Exactly, that method is root digit method.
Root digit method or lucky digit is the process of adding all the digits of a number till we get a single digit at the end i.e. between 0 – 9.

For example;
Simplification Questions in Bank Exams

Simplification Questions in Bank Exams

Cast 9 out to get quick results for simplification question in bank exams
You might wonder now how casting out 9 can help you reach the solution quick and accurate. Well, 9 is a very powerful number in mathematics as described in Vedic math. So when we use root digit method we can easily avoid 9 or any two digits that sums up to 9 while solving simplification questions in bank exams as it will not make any difference in the solution.
Simplification Questions in Bank Exams

Root digit should be balanced in LHS and RHS of Simplification questions in bank exams
Root digit of LHS = Root digit of  RHS.
Simplification Questions in Bank Exams
Simplification Questions in Bank Exams

Example 12: Simplification Questions in Bank Exams

Question: 15% of 524 – 2% of 985 +? = 20% of 423
1)25.9      2)27.7     3) 25.7    4)24.9    5) None of these

Solution:
Step 1:
15% of 524 = 78.6
2% of 985 = 19.7
20% of 423 = 84.6

Step 2:
By substituting the values
78.6 – 19.7 + ? = 84.6

Step 3:
To keep the unknown value positive, shift the equation on the right hand side.
? = 84.6 – 78.6 + 19.7
? = 6 + 19.7
? = 25.7

Therefore, the answer is option 3; 25.7
Simplification Questions in Bank Exams
Example 13: Simplification Questions in Bank Exams

Question: (1097.63 +  2197.36 – 2607.24) 3.5 = ?
1) 196.5     2)786.5   3)196.75    4)200.5     6)136.5

Solution:
Step 1: 
Find the root digit of the numbers.
Simplification Questions in Bank Exams
Step 2: 
As we now know the root digit, we need to balance the equation. We need to find a number whose digit when multiplied with 8 gives 6 as it's root product.
Option 1:  196.5 = 6 + 1 + 5 = 12 = 1+ 2 = 3 
Now, when 3 x 8 = 24 = 2 + 4 = 6
This option satisfies our condition as LHS = RHS

Option 2: 786.5 = 7 + 8 + 6 + 5 = 26 = 6 + 2 = 8 
Now, when 8 x 8 = 64 = 6 + 4 = 1

This option doesn't satisfy our condition as LHS is not equal to RHS.

Option 3: 196.75 = 1 + 6 + 7 + 5 = 19 = 1 + 9 = 1 
Now, when 1 x 8 = 8 

This option doesn't satisfy our condition as LHS is not equal to RHS

Option 4:  200.5 = 5 + 2 = 7 
Now, when 7 x 8 = 56 = 5+ 6 = 11 = 1 + 1 = 2 

This option doesn't satisfy our condition as LHS is not equal to RHS

Option 5:  136.5 = 1 + 5 = 6  
Now, when 6 x 8 = 48 = 4 + 8 = 12= 1 + 2 = 3

This option doesn't satisfy our condition as LHS is not equal to RHS 

As option 1 only satisfies the condition
Therefore, Option 1: 196.5 is the correct answer.


Example 14: Simplification Questions in Bank Exams

Question: 432 + 841 = ?2 + 1465
1) 15    2)65   3) 45   4)35    5)25

Solution:
Step 1: 
Find the root digit of the numbers.
Simplification Questions in Bank Exams
Step 2: 
As we now know that the root digit, we need to balance the equation such that when the unknown digit added to the digit 7 it gives a root digit as 8.

Option 1:  15 =  1 + 5 = 6 
Now, when 6 + 7 = 13 = 3 + 1 = 4
This option doesn't satisfy our condition as LHS is not equal to RHS.

Option 2: 65 = 6 + 5 = 11 = 1 + 1 = 2
Now, when 2 + 7 = 9

This option doesn't satisfy our condition as LHS is not equal to RHS.

Option 3: 45 = 4 + 5 = 10 = 1 
Now, when 1 + 7 = 8 

This option satisfies our condition as LHS = RHS

Option 4: 35 = 3 + 5 = 8 
Now, when 3 +7  = 10 = 1

This option doesn't satisfy our condition as LHS is not equal to RHS

Option 5:  25 = 2 + 5 = 7 
Now, when 7 + 7 = 14 = 1 + 4  = 5 

This option doesn't satisfy our condition as LHS is not equal to RHS 

As option 3 only satisfies the condition
Therefore, Option 3: 45 is the correct answer.

Well, now you might wonder whether Unit digit method is better or Root digit method for solving Simplification Questions in Bank Exams? Both methods are simple but when compared, unit digit method is quick and easy as we need to only find the unit digit of a number whereas root digit method involves adding all the digits, finding the root value and then checking all options with their root digit. It’s more of a time-consuming process.

Solve these couple of simplification questions for bank exams using Root Digit Method-
Question: 235.65 + 313.58 + 25 - 23.59 = ?
1) 550.64           2) 570.45              3) 450.46           4) 670.55              5) 580.45

Question: (14×7) - (11×5) = (2×12) + ?     
1) 17             2) 26                      3) 19             4) 20                      5) 22

Do tell us in the comment section how many seconds did it take for you to solve these simplification questions using unit digit method.

Stay tuned for our next post.
Simplification Questions in Bank Exams

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