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

Answer: (c)

Let the number be x

Then ${3x}/5 - {2x}/5 = 250$

x = 250 × 5 = 1250

Answer: (b)

quotient = 182.

Remainder = 182 – 175 = 7

Number N = 17 × 182 + 7

= 3101

Answer: (d)

Let the number are $a_1 = 10, a_2 = 20, a_3 = 25, a_4 = 40$ and $a_5 = 50$.

∴ Harmonic mean = $\text"Number of observations"/{1/a_1 + 1/a_2 + 1/a_3 + 1/a_4 + 1/a_5}$

= ${1/10 + 1/20 + 1/25 + 1/40 + 1/50}$

= $5/{{20 + 10 + 8 + 5 + 4}/200}$

= ${5 × 200}/47 = 1000/47 = 21.27 ≈ 21.3$

Answer: (c)

Divisibility Rule 11:

The difference between the sum of digit at odd place numbers and the sum of digit at even, place numbers is zero or multiple of 11.

Difference = 36 – 36 = 0, then it is divisible by 11.

Answer: (a)

Sum to be collected from 54 students = 60×54 = 3240 Rs.

Sum to be collected from 45 students = 3240

Amount contributed by 1 student = $3240/45$ = 72

∴ Additional amount to be paid by each student

72 – 60 = 12