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 5 of 13.

Nataraj said:   9 years ago
Please give the clarity to solve the problem.

Sravanthi said:   9 years ago
@Seema, you have done a good job.

RADHAKRISHNAN E said:   9 years ago
yes you are good @Seema.

RAGH said:   9 years ago
Find the product of the first 8 terms of a 15 number sequence whose 1st, 3rd, 5th numbers are 60, 45 and 30?

Renu said:   9 years ago
Thank you @Seema.

Bhavani said:   9 years ago
Thank you @Seema.

Karishma said:   9 years ago
896 * 2 = 1792.....?

Amrutha p nair said:   9 years ago
Friends. There is a simple way to get this answer.

Consider the unit digit means the last digit. Here in this question, 4 is the unit digit of 6374 and 5 is the unit digit of 625 and 1 is the unit digit of 341.

We want to find the unit digit. So avoid the other numbers.

So, the next step is a simple method we only using the logic behind the multiplication.

(4)^any odd no = 4.
(4)^any even no = 6.
(5)^any no = 5.
(1) any no =1 what I meant that.

4^1 = 4.
4^2 = 16.
4^3 = 64.

i.e, the unit digit are 4 & 6 and this is repeating. Did you get my point?

So by using this method.

(4) ^1793 * (5) ^317 * (1) ^491 = ?
4 * 5 * 1 = 20.

So the unit digit is 0.

Hope, this help you. Thank you.

Sai chandana said:   9 years ago
@Hemanth.

Your explanation was clear and good. Thanks!

Shital said:   10 years ago
(209*144) ^2+ (209*209) + (209*144) + (144*144) =?

Please tell me.


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