Find the unit digit:(76476756749)8754874878a)1b)2c)3d)4Correct answer is option 'A'. Can you explain this answer?

Question

Answer

Correct Answer :- a

Explanation : The unit digit of the number will depend on the last digit.

As we know that 9¹ = 9

9² = 81

9³ = 729

9⁴ = 6561

The unit digit of the number is 1 and 9, from the options we can pick the answer

Hence option a) is correct

Answer

Correct Answer :- a

Explanation : The unit digit of the number will depend on the last digit.

As we know that 91 = 9

92 = 81

93 = 729

94 = 6561

The unit digit of the number is 1 and 9, from the options we can pick the answer

Hence option a) is correct

Answer

Solution:
To find the unit digit of the given expression, we need to focus on the last digit of each term.

Multiplication of the following digits always gives the last digit as 9:
3 × 7
9 × 1
7 × 3
1 × 9

Therefore, we can write each term of the given expression as:
76476756749 = 9a + 4
8754874878 = 8b + 2

where a and b are some integers.

Now, we can rewrite the given expression as:
(9a + 4)(8b + 2)

Expanding this expression, we get:
72ab + 18a + 32b + 8

The unit digit of this expression will be the unit digit of 8 + 2 = 10.

Therefore, the unit digit of the given expression is 1, which is option (a).

Hence, option (a) is the correct answer.

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