1.
The average weight of 39 Students in a class is 23. Among them Sita is the heaviest while Tina is the lightest. If both of them are excluded from the class still the average remains same. The ratio of weight of Sita to Tina is 15:8.Then what is the weight of the Tina?
S+T = 23*(39-37) = 46 S/T = 15/8 T = 16
2.
The ages of Four members of a family are in the year 2010 are „X‟,‟X+12‟,‟X+24‟ and „X+36‟. After some years Oldest among them was dead then average reduced by 3. After how many years from his death, the average age will same as in 2010?
In 2010: 4x+72/4 = x+18 After death : 3x+36+3N/3 = x+18-3 N = 3 years 3x+36+3N/3 = (x+18) N = 6 years 6-3 = 3 years from his death
3.
The average of Four numbers is 24.5. of the four numbers, the first is 1.5 times the second, the second is 1/3 rd of the third, and the third is 2 times the fourth number. Then what is smallest of all those numbers?
First = 1.5x Second = x Third = 3x Fourth = 1.5x average = 24.5 = (1.5x+x+3x+1.5x)/4 x = 1
4.
There are 459 students in a hostel. If the number of students increased by 36, the expenses of the mess increased by Rs .81 Per day while the average expenditure per head reduced by 1. Find the original expenditure of the mess?
Total expenditure = 459x 36 students joined then total expenditure = 459x+81 average = 459x+81/495 = x-1 x = 16 original expenditure = 16*459 = 7344
5.
The average cost 32 different Mobiles is Rs. 9000. Among them, Oppo which is the costliest is 70% higher price than the cheapest Mobile Lava. Excluding those both mobiles, the average of the Mobiles is Rs.8880. Then what is the cost of Oppo Mobile
L+O = 21600 O = L*170/100 O = 13600
6.
The average age of a family of 9 members is 22 years. Surya is the youngest and his age is 6 years, then what was the average age of the family just before Surya was born?
7.
Dhoni scored 8000 runs in a certain number of innings. In the next five innings, he was out of form and hence, could make only 85 runs, as a result his average reduced by 1 run. How many innings did he play in total?
8000/n = a 8085/n+5 = a-1 n² + 90n – 40000 = 0 n = 160 n² + 5 = 165
8.
The weights of 19 people are in Arithmetic progression. The average weight of them is 19. If the heaviest is 37 Kgs. Then what is the weight of the Lightest?
19*19 = 19/2(2a+18d) 38= 2a+18d 37 = a+18d a = 1
9.
The average weight of 40 Students is 32. If the Heaviest and Lightest are excluded the average weight reduces by 1. If only the Heaviest is excluded then the average is 31. Then what is the weight of the Lightest?
40*32 = 1280 1280-H/39 = 31 H =71 1280-71- L/38 = 31 L = 31
10.
Average of 17 students in a class is X. When their marks are arranged in ascending order it was found to be in Arithmetic Progression. The class teacher found that rank the students who ranked 15th, 11th, 9th and 7th had copied the exam and hence they are suspended. Now the average of the remaining class is Y. Then
17X = 17/2 (2a+16d) X = a+8d 13Y = 17/2(2a+16d) – (4a+26d) Y = a+8.46d