2. The average weight of a class of 24 students is 35 kg. If the weight of the teacher be included, the average rises by 400 g. The weight of the teacher is
45
50
55
60
Answer: Option A
3. Average of first five multiples of 3 is
9
11
13
15
Answer: Option A
Explanation:
\begin{aligned}
Average = \frac{3(1+2+3+4+5)}{5} = \frac{45}{5} = 9
\end{aligned}
4. Average weight of 10 people increased by 1.5 kg when one person of 45 kg is replaced by a new man. Then weight of the new man is
50
55
60
65
Answer: Option C
Explanation:
Total weight increased is 1.5 * 10 = 15.
So weight of new person is 45+15 = 60
5. Marks of a student were wrongly entered in computer as 83, actual marks of that student were 63. Due to this mistake average marks of whole class got increased by half (1/2). Find the total number of students in that class.
25
30
35
40
45
Answer: Option D
Explanation:
Suppose total number of students are = X \begin{aligned} Total increase = x*\frac{1}{2} = \frac{x}{2} \\ => \frac{x}{2} = 83-63 = 20 \\ => x = 40 \end{aligned}