Aptitude - Square Root and Cube Root - Discussion

Discussion :: Square Root and Cube Root - General Questions (Q.No.5)

5. 

If 35 + 125 = 17.88, then what will be the value of 80 + 65 ?

[A]. 13.41
[B]. 20.46
[C]. 21.66
[D]. 22.35

Answer: Option D

Explanation:

35 + 125 = 17.88

35 + 25 x 5 = 17.88

35 + 55 = 17.88

85 = 17.88

5 = 2.235

80 + 65 = 16 x 5 + 65

   = 45 + 65

   = 105 = (10 x 2.235) = 22.35


Zee said: (Jun 12, 2011)  
VERY SIMPLE R80+6R5=4R5+6R5=10R5=10*2.235=22.35

M.V.Krishna/Palvoncha said: (Sep 11, 2011)  
Hello zee.

You are right. But we know R5 value. For higher root values above explanation process is must.

Sivajyothi said: (Apr 18, 2012)  
I don't know how to find roots for long numbers like 34567 can you please tell me that.

Nidhi Dahiya said: (Dec 15, 2014)  
Please tell me what is the meaning of 3 root 5? Is it 125, means cube of 5. I am little confused.

Poornamsh said: (Dec 18, 2014)  
Make square of 3R5 square of 3 = 9 & square of R5 = R5*R5 = 5.

This is the answer and meaning of 3R5.

Manoj Kumar said: (Dec 25, 2014)  
I am not understanding what you have solved explain it again briefly?

Amit said: (Feb 20, 2015)  
For better result you can consider it as follow:

The square root of 81 = 9*9 = 9.

So, the square root of 80 should be less then 9 lets guess it as 8.80.

Same way the square root of 4 = 2*2.

We can guest square root of 5 should be greater then 2 lets say it is 2.25.

Now 8.80+6*2.25 = 8.80+13.50 = 22.30.

Choose the nearest answer from our answer which is 22.35.

So answer = 22.35.

This is not accurate method this can be only use when you have very less time.

Khushb said: (May 24, 2015)  
How is 17.88 turn into 2.235 what 8 did here?

Vikas said: (Jun 14, 2015)  
Can anyone explain me the third step of explanation?

Mozzima said: (Jul 6, 2015)  
How you can eliminate 8 in 8r5?

Nanalal said: (Oct 3, 2015)  
Sir How to solve these questions?

R5456*R2120/R460.

Abhijit said: (Nov 20, 2015)  
How to calculate value of R5 manually?

Sukanto Karmakar said: (Dec 27, 2015)  
I want to know how to calculate value of R5 manually?

Taj said: (Feb 12, 2016)  
How to calculates R5 in short cut method?

Gargi Sarma said: (May 10, 2016)  
I don't understand this sum clearly. Can anyone help me to understand this?

Uma Mahesh said: (May 20, 2016)  
Could you please explain this problem clearly?

Mahi said: (Jul 8, 2016)  
Anyone please explain R5. I was more confused in that.

Divya said: (Oct 11, 2016)  
We have to divide 17.88 by 8, so root 5 = 2.235.

Viju said: (Dec 26, 2016)  
Can you please explain in simple method Hw it come 2.235?

Ashwini said: (Nov 11, 2017)  
Here you divide 17.88 by 8 then why you multiplied 2.235 by 10?

Sangay said: (Jul 23, 2018)  
If 35 + 125 = 17.88, then what will be the value of 80 + 65? Please explain.

Wrick said: (Nov 12, 2018)  
Easiest way is;

8√5=1788/100.
=> (10/8)*8√5 = (1788/100) * (10/8) = 223.5/10 = 22.35.

Honnu said: (Jun 6, 2019)  
Please anyone explain, How to calculate √5 value?

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