What is the unit digit in the product (365 x 659 x 771)?
2
4
6
Answer: Option C
Explanation:
Unit digit in 34 = 1 Unit digit in (34)16 = 1
Unit digit in 365 = Unit digit in [ (34)16 x 3 ] = (1 x 3) = 3
Unit digit in 659 = 6
Unit digit in 74 Unit digit in (74)17 is 1.
Unit digit in 771 = Unit digit in [(74)17 x 73] = (1 x 3) = 3
Required digit = Unit digit in (3 x 6 x 3) = 4.
7589 - ? = 3434
Answer: Option B
Let 7589 -x = 3434
Then, x = 7589 - 3434 = 4155
217 x 217 + 183 x 183 = ?
The unit digit in the product (784 x 618 x 917 x 463) is:
3
5
Answer: Option A
If the number 653 xy is divisible by 90, then (x + y) = ?
90 = 10 x 9
Clearly, 653xy is divisible by 10, so y = 0
Now, 653x0 is divisible by 9.
So, (6 + 5 + 3 + x + 0) = (14 + x) is divisible by 9. So, x = 4.
Hence, (x + y) = (4 + 0) = 4.
Unit digit in (34)16 = 1
Unit digit in 365 = Unit digit in [ (34)16 x 3 ] = (1 x 3) = 3