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

Answer: (e)

${x + x + 1 + x + 2 + x + 3}/4$ = 56.5

4x + 6 = 56.5 × 4

4x = 226 – 6 = 220

$x = 220/4$ = 55

A = 55, L = 57

Product = 55 × 57 = 3135

Answer: (a)

∴ Average age = 28.5

∴ Total age = 28.5 × 2 = 57

∴ Daughter's age = $5/19 × 57$ = 15 years

Answer: (c)

16a + 16b = 672

or, 16 (a + b) = 672

∴ a + b = $672/16$ = 42

Required average = ${a + b}/2 = 42/2$ = 21

Answer: (d)

Let the present ages of the father and son be 2x and x years respectively.

Then, (2x – 18) = 3 (x – 18) ⇔ x = 36.

∴ Required sum = (2x + x) = 3x = 108 years.

Answer: (b)

Let the third number be = x

∴ First number = 3x and

second number = ${3x}/2$

According to the question.

or, 3x + ${3x}/2$ + x = 3 × 121

or, ${6x + 3x + 2x}/2$ = 3 × 121

or, ${11x}/2$ = 3 × 121

∴ $x = {3 × 121 × 2}/11$ = 66

∴ Third number = 66

Required difference = 3x – x = 2x = 2 × 66 = 132