number system Model Questions & Answers, Practice Test for ibps rrb po officer scale 1 prelims 2024

Answer: (d)

Clearly, 4864 is divisible by 4.

So, 9P2 must be divisible by 3,

so, (9 + P + 2) must be divisible by 3.

∴ P = 1.

Answer: (b)

Unit digit in $7^4$ is 1.

Unit digit in $7^68$ is 1.

∴ Unit digit in $7^71 = 1 × 7^3$ = 3

Again, every power of 6 will give unit digit 6.

∴ Unit digit in $6^59$ is 6.

Unit digit in $3^4$ is 1.

∴ Unit digit in $3^64$ is 1.

Unit digit in $3^65$ is 3.

∴ Unit digit in $(7^71 × 6^59 × 3^65)$

= Unit digit in (3 × 6 × 3) = 4.

Answer: (d)

Answer: (d)

N = 8 7 9 8 5 4 6 * 5

Sum of odd digit places = 8 + 9 + 5 + 6 + 5 = 33

Sum of even digit places = 7 + 8 + 4 + * = 19 + *

Now, 33 – (19 + *) = 14 – *, it is divisible by 11, if value of * is 3.

Answer: (a)

Any number is not a square, if the unit's place digit of number may be 2, 3, 7, 8.

Hence, the number 9852 is not a square of any natural number.