number systems Model Questions & Answers, Practice Test for ibps so prelims

Answer: (d)

$(6{3}/5 - 3{4}/5) × 355 = (33/5 - 19/5) × 355$

= $({33 - 19}/5) × 355 = {14 × 355}/5 = 994$

Answer: (c)

Answer is LCM of 40, 42, 45

= $2^3 × 3^2 × 5^1 × 7^1$

= 2520 cm = 25.2 m.

Answer: (b)

$(n^3 – n) (n – 2)$

= $n (n^2 – 1) (n – 2)$

= n(n – 1) (n + 1) (n – 2)

= (n – 2) (n – 1)n(n + 1)

as n > 2 (natural number)

putting n = 3

= (n – 2) (n – 1) n(n + 1)

= (3 – 2) (3 – 1) 3(3 + 1)

= 1 × 2 × 3 × 4 = 24

So, option (c) is correct

Answer: (b)

Let the first odd number be x and the alternate odd number is x + 4

According to the question

x (x + 4) = 3x + 12

⇒ $x^2 + 4x = 3x + 12$

⇒ $x^2 + x – 12 = 0$

⇒ (x + 4) (x – 3) = 0

⇒ x = 3 (q x ≠ – 4)

Hence, the larger number is x + 4 = 3 + 4 = 7

Answer: (d)

963 × 788 = 758844