Number System Mcq Pdf Model Questions & Answers, Practice Test for ssc constables capfs nia ssf ar tier 1 2024

Answer: (d)

S = XYZ + YZX + ZXY

S = 100X + 10Y + Z + 100Y + 10Z + X + 100Z + 10X + Y

= 111 (X + Y + Z) = 3 × 37 (X + Y + Z)

∴ 3 digit number s is always divisible by 3, (x + y + Z) and 37, but not always divided by 9

Answer: (d)

Let the cost of a table be = Rs. x and that chair be = Rs. y

According to the question,

5x + 6y = Rs. 2884

∴ 3 × 5x + 3 × 6y = 3 × Rs. 2884

or, 15x + 18y = Rs. 8652

Answer: (b)

Consider $3^{4n} = (81)^n = (1 + 80)^n$ = 1 + 80q, q ∈ N

∴ $3^{3^{4n}} = 3^{80q + 1} = (81)^{20q} . 3$

Since the last digit of $(81)^{20q}$ is 1,

so the last digit of $3^{3^{4n}}$ + 1 is 1 × 3 + 1 = 4

Answer: (a)

Let the number be x.

∵ $x^2 + (56)^2 = 4985$

$x^2$ = 4985 – 3136 = 1849

∴ $x = √1849$ = 43

Answer: (d)

$17^256$

Last digit is 7 so

We know that 7 repeats its unit digit after 4 times.

= $(17)^{64×4}$

Unit of 7 × 7 × 7 × 7 = 2401

Now, 256 is completely divided by 4 so unit digit = 1