Aptitude - Square Root and Cube Root - Discussion

Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 4)
4.

1.5625 = ?

1.05
1.25
1.45
1.55
Answer: Option
Explanation:
   1|1.5625( 1.25
    |1
    |-------
  22| 56
    | 44
    |-------
 245| 1225
    | 1225
    |-------
    |    X
    |-------     

1.5625 = 1.25.

Discussion:
62 comments Page 2 of 7.

Pranitha said:   7 years ago
(15625/10000) ^1/2.

We have to cancel the above 2values.
Then we get (25/16) ^1/2,
= 5/4.
The ans is 1.25.
(3)

Hareesh said:   7 years ago
(15625/10000)^0.5.
= (15625^0.5)/{10^(4/2)},
= {(5*5*5)(5*5*5*)}^0.5/(10^2).
= 125/100,
= 1.25.

Rahul said:   7 years ago
@Varun

The 3rd step is;

{(5*5*5*5*5*5)/10*10*10*10)},
= 5*5*5/10*10,
= 125/100,
= 1.25.
(1)

Sidhu said:   8 years ago
@ALL.

Very simple short cut
1+5+6+2+5 = 8

[A]. 1.05(1+5)=6.
[B]. 1.25 (1+2+5)=8.
[C]. 1.45(1+4+5=10)=(1+0)=1.
[D]. 1.55(1+5+5=11)=(1+1)=)2.

So the answer is B.
(1)

Kiran said:   9 years ago
Thank you friends. It is easy to understand now.

Rudh said:   9 years ago
@Sandhya.

Thank you so much.

Laks said:   9 years ago
@Shalini and @Dipankar

Your method is Right.

Jay said:   9 years ago
From the above explanation We get the answer square root of 15625 = 125.

Now in the question the decimal digits are 4.

So in the answer we should have 4/2 = 2 digits in decimal after point so answer is 1.25.

Siva said:   10 years ago
1.25 *1.25.

If the last digits ends with 5 always in both the sides multiply 5*5.

Then in the first digit add one number.

12 + 1 = 13.

Now multiply 12*13 = 156.

This method will be more easy.

Som said:   10 years ago
Remember trick, in 15625 last two digits can be obtained by multiplying 5*5. Now 156 can be obtained by multi 12*13. So answer will be 125 now put decimal accordingly.


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