Model 3 Problems on average speed Section-Wise Topic Notes With Detailed Explanation And Example Questions
MOST IMPORTANT quantitative aptitude - 5 EXERCISES
The following question based on time & distance topic of quantitative aptitude
(a) 54 km/hr
(b) 55 km/hr
(c) 48 km/hr
(d) 50 km/hr
The correct answers to the above question in:
Answer: (c)
Using Rule 5,
Average speed
= $({2xy}/{x + y})$ kmph
= $({2 × 40 × 60}/{40 + 60})$ kmph
= 48 kmph
Discuss Form
Read more problems on average speed Based Quantitative Aptitude Questions and Answers
Question : 1
A train goes from Ballygunge to Sealdah at an average speed of 20 km/hour and comes back at an average speed of 30 km/hour. The average speed of the train for the whole journey is
a) 25 km/hr
b) 24 km/hr
c) 27 km/hr
d) 26 km/hr
Answer »Answer: (b)
UsingRule 5,
Required average speed
= ${2 × 30 × 20}/{30 + 20}$
[Since, Distance covered is same]
= ${2 × 30 × 20}/50 = 24$ kmph
Question : 2
A constant distance from Chennai to Bangalore is covered by Express train at 100 km/hr. If it returns to the same distance at 80 km/hr, then the average speed during the whole journey is
a) 88.98 km/hr
b) 88.89 km/hr
c) 90.20 km/hr
d) 88.78 km/hr
Answer »Answer: (b)
Using Rule 5,
If same distance are covered at two different speed of x and y kmph,
the average speed of journey = ${2xy}/{x + y}$
= $({2 × 100 × 80}/{100 + 80})$ kmph
= 88.89 kmph
Question : 3
A man goes to a place on bicycle at speed of 16 km/hr and comes back at lower speed. If the average speed is 6.4 km/hr in total journey, then the return speed (in km/hr) is :
a) 6
b) 4
c) 10
d) 8
Answer »Answer: (b)
Let the speed of cyclist while returning be x kmph.
Average speed = ${2 × 16 × x}/{16 + x}$
6.4 = ${32x}/{16 + x}$
6.4 × 16 + 6.4x = 32x
32x - 6.4x = 6.4 × 16
25.6x = 6.4 × 16
$x = {6.4 × 16}/{25.6}$ = 4 kmph.
Question : 4
A person went from A to B at an average speed of x km/hr and returned from B to A at an average speed of y km/hr. What was his average speed during the total journey ?
a) $2/{x + y}$
b) $1/x + 1/y$
c) ${x + y}/{2xy}$
d) ${2xy}/{x + y}$
Answer »Answer: (d)
Using Rule 5,
Required average speed = $({2xy}/{x + y})$ kmph
[Since, can be given as corollary If the distance between A and B be z units, then
Average speed = $\text"Totaldistance"/ \text"Time taken"$
= ${z + z}/{z/x + z/y}$
= $2/{1/x + 1/y} = 2/{{x + y}/{xy}} = {2xy}/{x + y}$
Question : 5
A man covers half of his journey at 6km/hr and the remaining half at 3km/hr. His average speed is
a) 4 km/hr
b) 3 km/hr
c) 9 km/hr
d) 4.5 km/hr
Answer »Answer: (a)
Using Rule 5,If a bus travels from A to B with the speed x km/h and returns from B to A with the speed y km/h,then the average speed will be $({2xy}/{x + y})$
If the same distance are covered at different speed of x kmph and y kmph,
the average speed of the whole journey is given by = $({2xy}/{x + y})$ kmph.
Required average speed
= ${2 × 6 × 3}/{6 + 3} = 36/9$ = 4 kmph
Question : 6
A boy rides his bicycle 10km at an average speed of 12 km/hr and again travels 12 km at an average speed of 10 km/hr. His average speed for the entire trip is approximately :
a) 11.0 km/hr
b) 12.2 km/hr
c) 10.4 km/hr
d) 10.8 km/hr
Answer »Answer: (d)
Total distance = 10 + 12 = 22 km
Total time = $10/12 + 12/10 = 244/120$ hours
Required average speed
= $\text"Total distance"/ \text"Total time"$
= $22/{244/120} = 22/244 × 120$ = 10.8 km/hr.
Using Rule 3,If a man travels different distances $d_1,d_2,d_3$, and so on with different speeds $s_1,s_2,s_3$, respectively then,Average speed = $({d_1 + d_2 + d_3 + ...})/{d_1/S_1 + d_2/S_2 + d_3/S_3 + ...}$
Here, $d_1 = 10, S_1 = 12, d_2 = 12, S_2$ = 10
Average Speed = ${d_1 + d_2}/{d_1/S_1 + d_2/S_2}$
= ${10 + 12}/{10/12 + 12/10} = {22 × 120}/244$ = 10.8 km/hrs.
GET time & distance PRACTICE TEST EXERCISES
Model 1 Basic Time & Distance using formula
Model 2 Vehicles in x/y of its usual speed
Model 3 Problems on average speed
Model 4 Time & Distance with Ratios
Model 5 Problems with Races
time & distance Shortcuts and Techniques with Examples
-
Model 1 Basic Time & Distance using formula
Defination & Shortcuts … -
Model 2 Vehicles in x/y of its usual speed
Defination & Shortcuts … -
Model 3 Problems on average speed
Defination & Shortcuts … -
Model 4 Time & Distance with Ratios
Defination & Shortcuts … -
Model 5 Problems with Races
Defination & Shortcuts …
Verbal Reasoning
Question & Answer Quiz
Non Verbal Reasoning
Question & Answer Quiz
Quantitative Aptitude
Question & Answer Quiz
Computer MCQ
Question & Answer Quiz
General English
Question & Answer Quiz
History GK
Question & Answer Quiz
Polity GK
Question & Answer Quiz
Geography GK
Question & Answer Quiz
Economy GK
Question & Answer Quiz
General Awareness GK
Question & Answer Quiz
Recently Added Subject & Categories For All Competitive Exams
100+ Quadratic Equation Questions Answers PDF for Bank
Quadratic Equation multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
IBPS Aptitude Linear Equations MCQ Questions Answers PDF
Linear equations multiple choice questions with detailed answers for IBPS RRB SO. more than 250 Attitude practice test exercises for all competitive exams
Continue Reading »
New 100+ Compound Interest MCQ with Answers PDF for IBPS
Compound Interest verbal ability questions and answers solutions with PDF for IBPS RRB PO. Aptitude Objective MCQ Practice Exercises all competitive exams
Continue Reading »
100+ Mixture and Alligation MCQ Questions PDF for IBPS
Most importantly Mixture and Alligation multiple choice questions and answers with PDF for IBPS RRB PO. Aptitude MCQ Practice Exercises all Bank Exams
Continue Reading »