Average test 6-Solved questions with detailed explanations for SSC, IBPS, SBI PO, RRB, RBI, CSE, CGL, CHSL, CDA, CSE, UPSC

6)

A car travels a certain distance from town A to town B at the speed of 42 km/hr and from town B to town A at a speed of 48 km/hr. What is the average speed of the car?

A)
45.8 km/hr
B)
44.8 km/hr
C)
78 km/hr
D)
65 km/hr
E)
None of these

Answer: Option B

Explanation

According to the question

We know the formula,

Average speed= $\frac{2 AB}{A + B} km / hr$

∴ Average speed iof the car= $\frac{2 \times 42 \times 48}{42 + 48} = \frac{4032}{90}$

= 44.8 km/hr

Hence, Option B is correct.

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Discussion

7)

A man divides his total route of journey into three equal parts and decides to travel the three parts with speed of 15 km/hr, 10 km/hr and 5 km/hr, respectively. Find his average speed of during journey?

A)
12.8 km/hr
B)
84.6 km/hr
C)
8.18 km/hr
D)
9.12 km/hr
E)
None of these

Answer: Option C

Explanation

According to the question

we know the formula,

Average speed during whole journey= $\frac{3 ABC}{AB + BC + CA} km / hr$

∴Required average speed = $= \frac{3 \times 15 \times 10 \times 5}{15 \times 10 + 10 \times 5 + 15 \times 5} = \frac{2250}{150 + 50 + 75} = \frac{2250}{275}$

= 8.18 km/hr

Hence, Option C is correct.

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Discussion

8)

Mr bunny travels in his car and covers $\frac{1}{4}$ part of his journey with 8 km/hr, $\frac{3}{5}$ part with 6 km/hr and remianing $\frac{3}{20}$ part with a speed of 10 km/hr. Find out his average speed during the whole journey?

A)
6.83 km/hr
B)
8.89 km/hr
C)
9.67 km/hr
D)
5.87 km/hr
E)
None of these

Answer: Option A

Explanation

According to the average speed formula,

P= $\frac{1}{4}$ , Q= $\frac{3}{5}$ , R= $\frac{3}{20}$

X= 8 km/hr, Y= 6km/hr, Z=10 km/hr

∴ Required average speed

$= \frac{1}{\frac{P}{X} + \frac{Q}{Y} + \frac{R}{Z}} = \frac{1}{\frac{1}{4 \times 8} + \frac{3}{5 \times 6} + \frac{3}{20 \times 10}} = \frac{1}{\frac{1}{32} + \frac{1}{10} + \frac{3}{200}} = \frac{1}{\frac{25 + 80 + 12}{800}} = \frac{800}{117} = 6.83 km / hr$

Hence, Option A is correct.

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Discussion

9)

A person covers 9 km with a speed of 3 km/hr. 25 km with a speed of 5 km/hr and 30 km with a speed of 10 km/hr. Find out the average speed of person?

A)
$11 \frac{5}{9} km / hr$
B)
$9 \frac{5}{11} km / hr$
C)
56 km/hr
D)
$5 \frac{9}{11} km / hr$
E)
None of these

Answer: Option D

Explanation

Given,

P= 9 km/hr, Q=25 km, R=30 km

X= 3 km/hr, Y =5 km/hr, Z=10 km/hr

∴ Required average speed $= \frac{P + Q + R}{\frac{P}{X} + \frac{Q}{Y} + \frac{R}{Z}}$

$= \frac{9 + 25 + 30}{\frac{9}{3} + \frac{25}{5} + \frac{30}{10}} = \frac{64}{3 + 5 + 3} = \frac{64}{11} = 5 \frac{9}{11} km / hr$

Hence, Option D is correct.

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Discussion

10)

Abdul covers first half of his total journey with a speed of 25 km/hr and the next half with a speed of 40 km/hr. Find out the average speed of Abdul during complete journey?

A)
$30 \frac{10}{13} km / hr$
B)
$4 \frac{10}{13} km / hr$
C)
$8 \frac{10}{13} km / hr$
D)
$6 \frac{10}{13} km / hr$
E)
None of these

Answer: Option A

Explanation

Given,

A=25 km/h, B=40 km/h

∴ Average speed= $\frac{2 AB}{A + B}$ = $\frac{2 \times 25 \times 40}{25 + 40}$

= $\frac{2 \times 5 \times 40}{13}$

= $\frac{400}{13} = 30 \frac{10}{13} km / h$

Hence, Option A is correct.

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Discussion

Average Test-6 (Calculating average Speed)

Answer: Option B

Answer: Option C

Answer: Option A

Answer: Option D

Answer: Option A