Ques 1 Of Average problems, : The Average age of 10 students in a class is 20 years. If a new student is included then the new average age of students increased by 1 year. The age of new student is.
21×1+10×1=31 year Ans.
Ques of average problems : The Average Weight of 20 four wheelers is 180 kg. If an old car is removed from this group of four wheelers. the new average weight decreased by 2 kg . the weight of the removed car is.
178×-1+20×-2=218 kg Ans.
Ques 3 : The Average age of 6 servants in my house is 28 year. A new young Servant Replace an old servant then the new average Reduce by 1 year. The age of servant is.
27×0+6×-1= -6 Can not Determined
* Because the age of new /old servant is not given,in this case answer will be CND.
* if we were given the age of old servant than;
- If old servant age is 31 then find new servant age.
31 – 6 = 25 year
- if new servant age is 25 year then find old servant age.
25 + 6 = 31 year
Ques 4 : The average weight of A,B,C,D is 40 kg. A new person E included in this group then the average weight of the group is increase by 1 kg Again a new person F replace A then the new average of 5 persons become 42. The average Weight of B,C,D and F is.
F,B,C,D,E=5×42=210 → E=45 kg
So F,B,C,D=210-45=165 kg
Average weight of B,C,D,F is 165÷4 = 41.25 kg Ans.
Ques 5 : The average age in a class is 15 years. Average age increase by 0.2 years in a class after taking admission of 10 new students.Find the average of new students in the class.
Average of new students is 160÷10=16 year Ans.
Ques 6 : 4 Boys and 3 Girls Spent Rs. 120 on an average, of which boys spent 150 on the average. Then the average amount spent by the Girls is.
By Traditional Method
According to the question
Average: 4B + 3G = Rs. 120
Sum: 4B + 3G = 120×7 = Rs. 840
Average: 4B = 150×4 = Rs. 600
Sum of Girls = 840 – 600 = Rs. 240
Average of Girls = 240÷3= Rs. 80
By Alligation Method
120 – x = 40
X = 120 – 40
X = 80 Ans.