Aptitude - Numbers - Discussion
Discussion Forum : Numbers - General Questions (Q.No. 10)
10.
What is the unit digit in {(6374)1793 x (625)317 x (341491)}?
Answer: Option
Explanation:
Unit digit in (6374)1793 = Unit digit in (4)1793
= Unit digit in [(42)896 x 4]
= Unit digit in (6 x 4) = 4
Unit digit in (625)317 = Unit digit in (5)317 = 5
Unit digit in (341)491 = Unit digit in (1)491 = 1
Required digit = Unit digit in (4 x 5 x 1) = 0.
Discussion:
124 comments Page 2 of 13.
Pooja said:
7 years ago
As in 6374 = unit digit is '4'
in 625 = unit digit is '5'
in 341 = unit digit is '1'.
Now just multiply all the digit units =4 * 5 * 1=20
In 20, the unit digit is '0'.
Again,
In the power of 6374 i.e,1793 = unit digit is '3',
In the power of 625 i.e, 317 = unit digit is '7',
In the power of 341 i.e, 491 = unit digit is '1',
Now multiply all the digit units = 3*7*1=21.
In 21, the unit digit is '1'.
Hence,
The required unit digit is, 0^1.
= 0 (answer).
in 625 = unit digit is '5'
in 341 = unit digit is '1'.
Now just multiply all the digit units =4 * 5 * 1=20
In 20, the unit digit is '0'.
Again,
In the power of 6374 i.e,1793 = unit digit is '3',
In the power of 625 i.e, 317 = unit digit is '7',
In the power of 341 i.e, 491 = unit digit is '1',
Now multiply all the digit units = 3*7*1=21.
In 21, the unit digit is '1'.
Hence,
The required unit digit is, 0^1.
= 0 (answer).
(2)
Rajesh Kaibarta said:
2 years ago
Very good explanation, Thanks all.
(2)
Hemanth said:
2 decades ago
This can be done in a simpler manner.
The unit digit of 625^x is 5.
The unit digit of 6374^y is an even number.
When multiplied, the unit digit must be 0.
The unit digit of 625^x is 5.
The unit digit of 6374^y is an even number.
When multiplied, the unit digit must be 0.
Vaibhav said:
2 decades ago
Thanks.
A.Athiban Sakthivel said:
2 decades ago
How unit digit in [(4^2)896 x 4] is equal to Unit digit in (6 x 4) = 4 ?
Supreet singh said:
2 decades ago
I too. !
But hemanth method is good.
But hemanth method is good.
Hanah said:
2 decades ago
@Hemanth I still can't understand your method.
Don said:
2 decades ago
What happend? jus can't understand. Hemanth method is good but what if it is 622^ () then wat?
Anitha said:
2 decades ago
I can't understand.
Revathi said:
2 decades ago
I cant understand... explain (6*4)....
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers