100+ Number System Questions for Bank PO Exams Pdf - 1

Ans: D

3⁴ gives unit digit 1.

So, (3⁴)²⁴ gives unit digit 1.

And, 3³ gives unit digit 7.

∴ 3⁹⁹ = (3⁴)²⁴ × 3³ gives unit digit (1 x 7) i.e. 7.

Ans: B

(1³ - 1) = 0, (2³ - 2) = 6, (3³ - 3) = 24, (4³ - 4) = 60 and so on, each one of which is divisible by 6.

Ans: C

Let the four consecutive even numbers be a, a + 2, a + 4 and a + 6.

Then, a + a + 2 + a + 4 + a + 6 = 180 ⇒ 4a = 168 ⇒ a= 42.

So, these numbers are 42, 44, 46 and 48.

Sum of next four consecutive even numbers = (50 + 52 + 54 + 56) = 212.

Ans: D

(106 × 106 - 94 × 94)

= (106)² - (94)²= (106 + 94) (106 - 94) = (200 × 12) = 2400.

Ans: C

(24 + 25 + 26)² - (10 + 20 + 25)² = (75)² - (55)²

= (75 + 55) (75 - 55) = (130 × 20) = 2600.