Average ( SET 1 : Q1-Q5 )

 1.The average weight of 48 students of a class is 36 kg. If the weights of teacher and principal are included, then thee average becomes 36.76 kg. Find the sum of the weights of teacher and principal? 

1
108 kg
2
112 kg
Incorrect
3
110 kg
Correct Answer
4
114 kg


Solution: 3

Sum of weights of teacher and principal

⇒ New avg. × No. of students – Existing avg. × No. of students

⇒ 36.76 × 50 – 36 × 48 = 1838 – 1728

⇒ 110 kg

∴ Sum of weight of teacher and principle is 110 kg


2.Average marks obtained by 40 students is 56. If the average marks of 8 students who failed in the examination are 10, what are the average marks of students who passed the examination?
1
67.50
Correct Answer
2
42.45
Incorrect
3
76.55
4
64.50


Solution: 1

Average marks = (Total marks of the students)/(Total number of students)

Average marks obtained by 40 students = 56

Total marks obtained by 40 students/40 = 56

∴ Total marks obtained by 40 students = 56 × 40 = 2240

Average marks of 8 students who failed in the examination = 10

Marks obtained by failed students/8 = 10

∴ Marks obtained by failed students = 10 × 8 = 80

Total marks obtained by passed students = 2240 - 80 = 2160

∴ Average marks of passed students = 2160/(40 - 8) = 2160/32 = 67.5



3. If a hostel’s mess owner expends Rs. 5000 on vegetables, Rs. 3000 on spices and Rs. 6500 on gas services per month for 50 students then what is the monthly average expenditure per student of his hostel’s mess.
1
Rs. 260
2
Rs. 270
Incorrect
3
Rs. 290
Correct Answer
4
Rs. 280


Solution: 3

Total expenditure = vegetables + spices + gas services

⇒ Total expenditure = 5000 + 3000 + 6500 = 14500

∴ Average Expenditure per student = 14500/50 = Rs. 290


4. The average salary of Sanjay from January to June is Rs. 12000 and from July to September is Rs. 13000 and for last 3 months the average salary is Rs. 1500 more than July to September. Find the average annual salary of Sanjay.
1
Rs. 12785
2
Rs. 12585
Incorrect
3
Rs. 12675
4
Rs. 12875
Correct Answer


Solution: 4

⇒ Total salary from Jan. to June = 12000 × 6 = 72000

⇒ Total salary from July to September = 13000 × 3 = 39000

⇒ Average salary from Oct. to Dec. = Avg. salary from July to Sep. + 1500

⇒ Total salary from Oct. to Dec. = (13000 + 1500) × 3 = 43500

⇒ Annual average salary of Sanjay = (72000 + 39000 + 43500)/12

⇒ 154500/12

∴ Annual average salary of Sanjay = Rs. 12875


5. The average expenditure of Mahesh for the January to June is Rs. 8400 and he spends Rs. 2400 in January and Rs. 3000 in July. The average expenditure for the months of February to July is:
1
Rs. 8500
Correct Answer
2
Rs. 5100
Incorrect
3
Rs. 4800
4
Rs. 6000

Solution: 1

⇒ Average expenditure of Mahesh from Jan to June = Total expenditure/6 = 8400

⇒ Total expenditure = 8400 × 6 = 50400

⇒ Total expenditure from Feb to June = 50400 – 2400 = 48000

⇒ Total expenditure from Feb to July = 48000 + 3000 = 51000

⇒ Average expenditure from Feb to July = 51000/6 = 8500

∴ required average expenditure of Mahesh from Feb to July is Rs. 8500

 SET 01 : Q1 - Q5

 SET 05 : Q21 - Q25

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