Fast way to solve average questions with tricks for Bank Exams

1

The average annual income (in Rs.) of certain agricultural workers is P and that of other workers is Q . The number of agricultural workers is 9 times that of other workers. Then the average monthly income (in Rs.) of all the workers is :

» Explain it

Correct Option: D

Let the number of other workers be x.

Then, number of agricultural workers = 9x.

Total number of workers = 9x + x = 10x.

So, Average monthaly income

=	P x (9x) + Q x (x)	=	x[9P + Q ]
	10x		10x

	=	(9P + Q)
		10

1

कुछ कृषि श्रमिकों की औसत वार्षिक आय (रुपये में) P है और अन्य श्रमिकों की औसत वार्षिक आय Q है। कृषि श्रमिकों की संख्या अन्य श्रमिकों की तुलना में नौ गुना अधिक है। तो सभी श्रमिकों की औसत मासिक आय (रुपये में) है:

» Explain it

सही विकल्प : D

Let the number of other workers be x.

Then, number of agricultural workers = 9x.

Total number of workers = 9x + x = 10x.

So, Average monthaly income

=	P x (9x) + Q x (x)	=	x[9P + Q ]
	10x		10x

	=	(9P + Q)
		10

2

A family consist of grandparents, parents and two grandchildren. The average age of the grandparents is 56 years, that of the parents is 27 years and that of the grandchildren is 7 years. What is the average of the family?

» Explain it

Correct Option: C

First, we find out the normal ages of candidates:

Grand parents(2 candidates) = 56 x 2

Parents (2 candidates) = 27 x 2

Two grandchildren = 7 x 2.

The total candidates are 6. then,

Average =	56 x 2 + 27 x 2 + 7 x 2	⇒	112 + 54 + 14
	2 + 2 + 2		6

=	180	= 30 years
	6

2

एक परिवार में दादा-दादी, माता-पिता और दो नाती-पोते हैं। दादा-दादी की औसत आयु 56 वर्ष है, माता-पिता की 27 वर्ष और पोते की औसत आयु 7 वर्ष है। परिवार का औसत कितना है?

» Explain it

सही विकल्प : C

First, we find out the normal ages of candidates:

Grand parents(2 candidates) = 56 x 2

Parents (2 candidates) = 27 x 2

Two grandchildren = 7 x 2.

The total candidates are 6. then,

Average =	56 x 2 + 27 x 2 + 7 x 2	⇒	112 + 54 + 14
	2 + 2 + 2		6

=	180	= 30 years
	6

3

A library has an average of 430 visitors on Sundays and 270 on other days. The around average of the number of visitors per day in a month of 31 days beginning with a Saturday is:

» Explain it

Correct Option: D

Since the month begins with a saturady , So there will be five sundays in the month,

Req. Avg. =	430 x 5 + 270 x 26	⇒	2150 + 7020
	31		31

⇒	9170	= 295.80 ≈ 296.
	31

So, the arround value of vistiors per day is 296.

3

एक पुस्तकालय में रविवार को औसतन 430 और अन्य दिनों में 270 आगंतुक आते हैं। शनिवार से शुरू होने वाले 31 दिनों के महीने में प्रति दिन आगंतुकों की संख्या का लगभग औसत है:

» Explain it

सही विकल्प : D

Since the month begins with a saturady , So there will be five sundays in the month,

Req. Avg. =	430 x 5 + 270 x 26	⇒	2150 + 7020
	31		31

⇒	9170	= 295.80 ≈ 296.
	31

So, the arround value of vistiors per day is 296.

4

If the average marks of three batches of 40, 50 and 60 students respectively is 30, 50 and 70, then the average marks of all the students is:

» Explain it

Correct Option: B

Req Avg =	40 x 30 + 50 x 50 + 60 x 70
	30 + 50+ 70

⇒	1200 + 2500 + 4200
	150

⇒	7900	= 52.66
	150

Hence, option (B) is correct.

4

यदि 40, 50 और 60 छात्रों के तीन बैचों के औसत अंक क्रमश: 30, 50 और 70 हैं, तो सभी छात्रों के औसत अंक होंगे:

» Explain it

सही विकल्प : B

Req Avg =	40 x 30 + 50 x 50 + 60 x 70
	30 + 50+ 70

⇒	1200 + 2500 + 4200
	150

⇒	7900	= 52.66
	150

Hence, option (B) is correct.

5

The average weight of 18 boys in a class is 45.55 kgs and that of the remaining 4 boys is 35.25 kgs. Find the average weight of all the boys in the class.

» Explain it

Correct Option: C