averages Model Questions & Answers, Practice Test for ibps rrb po prelims

Answer: (a)

Let the consecutive odd numbers be

x, x + 2, x + 4, x + 6 and x + 8

According to the question.

${x + x + 2 + x + 4 + x + 6 + x + 8}/5 = 41$

or, 5x + 20 = 41 × 5 = 205

or, 5x = 205 - 20 = 185

∴ $x = 185/5$ = 37

∴ A = 37 and E = 37 + 8 = 45

Required product = 37 × 45 = 1665

Answer: (b)

Let the average of batsman after 11th innings = A

$\text"Total score made by batsman at the end of 11th innings"/11$ = A

∴ Total score after 11th innings = 11 A

Now, $\text"Total score after 11th innings + score made in 12th innings"/12$ = A + 2

⇒ 11A + 63 = (A + 2) × 12

⇒ 11A - 12 A = 24 - 63

⇒ A = 39

12th innings average = 39 + 2 = 41

Answer: (e)

Sum of four integers = 73.5 × 4 = 294

∴ Sum of two middle integers

= 294 - (108 + 29) = 157

Difference between two integers = 15

∴ The smaller number

= ${157 - 14}/2$ = 71

Answer: (b)

All such 2 digt numbers whose digits are same, 11, 22, 33, 44 .... upto 99

Average = sum/9 = $(11 + 22 + 33+ .....+ 99)/9 = 55$

Answer: (d)

Short-cut method:

Weight of new crewmen

= Replace man weight + [No. of crew men × increased average]

= 55 + 12 × $1/3$ = 59 kg