Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 5)
5.
1397 x 1397 = ?
Answer: Option
Explanation:
| 1397 x 1397 | = (1397)2 |
| = (1400 - 3)2 | |
| = (1400)2 + (3)2 - (2 x 1400 x 3) | |
| = 1960000 + 9 - 8400 | |
| = 1960009 - 8400 | |
| = 1951609. |
Discussion:
55 comments Page 3 of 6.
Shweta said:
7 years ago
Nice explanations thank you all.
Ajith said:
8 years ago
@Isha.
Whether it is applicable to all type of problems like this?
Whether it is applicable to all type of problems like this?
Sowmi said:
8 years ago
Nice explanation @Rahul Jadhav.
Isha said:
8 years ago
1+3+9+7=20 =>2+0=2.
1+3+9+7=20 =>2+0=2.
2+2=4.
a) 1+9+5+1+6+0+9=31 =>3+1=4 (4 equal to 4) so it is answer.
b)1+9+8+1+7+0+9=35 =>3+5=8 (8 not equal to 4) wrong.
1+3+9+7=20 =>2+0=2.
2+2=4.
a) 1+9+5+1+6+0+9=31 =>3+1=4 (4 equal to 4) so it is answer.
b)1+9+8+1+7+0+9=35 =>3+5=8 (8 not equal to 4) wrong.
Rohit said:
8 years ago
Just multiply.
1397
1397
After multiplying for the second time just add and see the last 3digits are coming to 609 then its easy to ascertain or you can take the nearest whole number, whichever seems easy for you.
1397
1397
After multiplying for the second time just add and see the last 3digits are coming to 609 then its easy to ascertain or you can take the nearest whole number, whichever seems easy for you.
Pratheev Kalyan said:
8 years ago
1397*1397=?
Since 1400*1400=1960000, so the result must be less than 1960000. By this, options c and d gets eliminated. Remaining is a and b.
The number 1397 is divisible by 11. So, the answer must also be divisible by 11. Thus option b(not divisible by 11) is eliminated and option a is the answer.
Since 1400*1400=1960000, so the result must be less than 1960000. By this, options c and d gets eliminated. Remaining is a and b.
The number 1397 is divisible by 11. So, the answer must also be divisible by 11. Thus option b(not divisible by 11) is eliminated and option a is the answer.
Jaishanth said:
8 years ago
@Kabita.
We should just minus the 3 from 1400 to make the formula=(a-b)^2.
1397=(1400-3).
We should just minus the 3 from 1400 to make the formula=(a-b)^2.
1397=(1400-3).
Kabita said:
8 years ago
@Sindu.
Please tell me How 3 came?
Please tell me How 3 came?
Sindu said:
8 years ago
1397*1397= (1397*1000)+(1397*400)-(1397*3) = 1951609.
Split 1397 as (1000+400-3).
Split 1397 as (1000+400-3).
Nagarjuna goud said:
9 years ago
Hi @Sravani.
I did not understand your answer how it came?
I did not understand your answer how it came?
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