number system Model Questions & Answers, Practice Test for ssc chsl tier 1 2023

Answer: (a)

A + A + 2 + A + 4 + A + 6 = 180

4A + 12 = 180

A = 42.

∴ Next four consecutive even numbers are

50 + 52 + 54 + 56 = 212

Answer: (a)

Here, 88 = 2 × 2 × 2 × 11= $(2)^3 × (11)^1$

$91 = (7)^1 × (13)^1$

96 = 2 × 2 × 2 × 2 × 2 × 3 = $(2)^5 × (3)^1$

and 99 = 3 × 3 × 11 = $(3)^2 ×(11)^1$

So, 91 has least number of divisors.

Answer: (a)

$(18^2 – 1) = (17) (18 + 1)$

$(18^4 – 1) = (18^2 + 1) (18^2 – 1)$

= $(18^2 + 1) (18 + 1) (18 – 1)$

$(18^6 – 1) = (18^3)^2 – 1$

= $(18^3 + 1) (18^3 – 1)$ = 17 × k etc.

Hence there will only 9 times 17 in the whole expression.

Answer: (d)

Lowest number of set A = $280/5$ – 4 = 52

Lowest number of other set = 52 × 2 – 71 = 33

Required sum = 33 + 34 + 35 + 36 + 37 = 175

Answer: (b)

$55^3 + 17^3 - 72^3 = (55)^3 + (17)^3 - (55 + 17)^3$

= $55^3 + 17^3 - (55)^3 - (17)^3 - 3 × 55 × 17 × 72$

= $- 3 × 55 × 17 × 72$