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

Answer: (c)

When N is a natural number, then there is only one possible case that N, (N + 2), (N + 4) are prime numbers when N = 3, then N, (N + 2), (N + 4) = 3, 5, 7 all are primes.

Answer: (a)

Let the smaller number be $x$

∵ $x × (x + 2)$ = 4488

⇒ $x^2 + 2x – 4488$ = 0

⇒ $(x + 68) (x – 66)$ = 0

∴ $x$ = 66

Also, from the given alternatives, it could be ascertained that 66 × 68 = 4488

Answer: (a)

$x - 600 × 75/100 × 2/3 = 320$

$x = 320 + {600 × 75 × 2}/{100 × 3} = 620$

Answer: (b)

Sum of all the digits in the number (26492518)

= 2 + 6 + 4 + 9 + 2 + 5 + 1 + 8 = 37

When we subtract 4 from 37 then number must be divisible by 3.

Answer: (c)

Let the numbers be the form 10x + y

According to question

10x + y = x + y + xy

9x = xy

∴ y = 9

The numbers are 19, 29, 39, 49, 59, 69, 79, 89 and 99 total of 9 numbers

Hence the required fraction

= $9/91$ = 0.099 ≈ 0.1