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)}?
2
3
5
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 12 of 13.

Keerthinayak said:   6 years ago
Thanks @Seema.

Nilkanta Das said:   6 years ago
Nice explanation, Thanks all.

Shivam rana said:   6 years ago
Thanks @Seema.

Harry said:   6 years ago
Thanks @Pooja.

Sandeep said:   6 years ago
The easiest way is in 1793 we take last two digits and 4 divide by means 93÷4 the remainder is 1 so in 6374 the unit digit is 4 so 4^1 is 4.

The answer is 4*5*1=20 unit digit is 0.

Prajna Samal said:   6 years ago
What is short trick of this sum? I can't understand easily.

Sumanth said:   6 years ago
You mentioned method is suitable for all the unit digit problems.

Kanimozhi said:   6 years ago
What is short trick of this sum? I can't understand easily.

Vamsi krishna said:   6 years ago
First, we can add the last unit digits without considering powers.
4+5+1=10.

The above 10 last digits was zero.

Reza Khan(BD) said:   6 years ago
We know,

(4)^n=unit digit 4; if n=even number.
Cause 4^(1/3/5) = unit digit 4.
So, 4^1793 gives unit digit 4.


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