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:
123 comments Page 10 of 13.
Dibakara nayajk said:
1 decade ago
4* 4 = 16 - 6 ->2
16 *4 = 84 - 4 ->3
5 * n = ..5
1 8 n = 1
(6 /4 ) * 5 * 1 = ......0
so ans is 0;
16 *4 = 84 - 4 ->3
5 * n = ..5
1 8 n = 1
(6 /4 ) * 5 * 1 = ......0
so ans is 0;
Prabagaran said:
1 decade ago
No. How to separate this sequence [(42)896 x 4].
Sasi said:
1 decade ago
When finally mutilpled (4*5*1) we get 20. Consider the 20, the last digit ill be the unit digit. So the answer is 0,
Got it.
Got it.
Abc said:
1 decade 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.
How?
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.
How?
Aruna said:
1 decade ago
Unit digit means last digit..
5^(anything) is ending with 5..
So for our convenience it s considered as 5.
5^(anything) is ending with 5..
So for our convenience it s considered as 5.
Swetha said:
1 decade ago
Seema 's method is too good. It saves time. Thank you seema.
Dharmraj said:
1 decade ago
Why are you consider (5) the power 317 is digit unit is 5? please explain it.
Shashank said:
1 decade ago
@gautham. You made it very simple!
Thanks.
Thanks.
Gaurav said:
1 decade ago
Seema is right. I like her method. The way of approaching is good. Toooooo much.
Vasanthi said:
1 decade ago
@Karthi
Unit digit means last digit.
Unit digit means last digit.
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