number system Model Questions & Answers, Practice Test for ibps clerk prelims

Answer: (d)

A + C = 146

or A + A + 4 = 146

or A = ${146 - 4}/2 = 71$

∴ E = A + 8 = 71 + 8 = 79

Answer: (e)

Let the two digits be x and y.

Then, x + y = 15 ... (i)

x – y = 3 ... (ii)

from equation (i) and (ii),

x = 9, y = 6

∴ Product = 9 × 6 = 54

Answer: (b)

Product of first fifty positive consecutive integers

= 1 × 2 × .... × 50 = 50 !

Largest possible value of n = $[50/7] + [50/7^2]$

= 7 + 1 = 8

Answer: (d)

$(7)^139 = 7^{4(34)+3}$

unit digit of $7^{4n}$ is 1 and $7^3$ = 34 is 3

than unit digit = 1 × 3 = 3

Answer: (a)

In the given range, the last number which is divisible by both 5 and 7. i.e., 35 is 210 and the highest number is 770.

So the total number of numbers between 200 and 800 which are divisible by both 5 and 7 is

$({770 - 210}/35) + 1 = 17$

Hence option (c) is correct.