averages Model Questions & Answers, Practice Test for ssc cgl tier 2

Answer: (c)

Let the ages of Abhay and his father 10 years ago be x and 5x years respectively. Then,

Abhay's age after 6 years

= (x + 10) + 6 = (x + 16) years.

Father's age after 6 years

= (5x + 10) + 6 = (5x + 16) years.

∴ (x + 16) = $3/7$(5x + 16)

⇔ 7 (x + 16) = 3 (5x + 16)

⇔ 7x + 112 = 15x + 48

⇔ 8x = 64 ⇔ x = 8.

Hence, Abhay's father's present age

= (5x + 10) = 50 years.

Answer: (b)

Required average

= ${965 + 362 + 189 + 248 + 461 + 825 + 524 + 234}/8$

= $3808/8 = 476$

Answer: (c)

Total weight of 150 students

= 150 × 60 = 9000 kg

Let total no. of boys = x

No. of girls = 150 – x

Average weight = ${x × 70 +(150 - x)55}/150$

⇒ 60 = ${70x + 150 × 55 - 55x}/150$

⇒ 60 × 150 = 15x + 150 × 55

⇒ 15x = 60 × 150 – 150 × 55

∴ $x = 750/15 = 50$

∴ No. of boys in the class = 50

Answer: (b)

The weight of the boxes are 1st box → 200, 3rd box → 250 kg, 2nd box → 300 kg, 4th box → 350 and 5th box → 500 kg.

Hence difference between the heavier 4 and the lighter 4 is 300.

Hence, difference in the averages is 75.

Answer: (b)

Required average marks

= ${40 × 50 + 35 × 60 + 45 × 55 + 42 × 45}/{40 + 35 + 45 + 42}$

= ${2000 + 2100 + 2475 + 1890}/162$

= $8464.9997/162$ = 52.25