Exercise : Average - General Questions
✔ Average -
General Questions
21.
The average of 20 numbers is zero. At most, how many can be greater than zero?
View Answer
Answer: Option C
Explanation:
Explanation:
To keep the sum zero, you can have 19 positive numbers balanced by one very large negative number.
22.
Avg of A, B, C is 84kg. D joins, avg is 80kg. E (D+3kg) replaces A, avg of B, C, D, E is 79kg. Find A's weight.
View Answer
Answer: Option B
Explanation:
Explanation:
\(A+B+C=252\); \(A+B+C+D=320 \implies D=68, E=71\). \(B+C+D+E=316 \implies B+C=177\). \(A = 252 - 177 = 75\) kg.
23.
If each of 10 numbers is increased by 10%, what is the percentage increase in the average?
View Answer
Answer: Option C
Explanation:
Explanation:
If every value in a dataset increases by a certain percentage, the sum and the average also increase by that same percentage.
24.
A man spends $1800/mo for 4 months, $2000/mo for 8 months, and saves $5600/yr. Find his average monthly income.
View Answer
Answer: Option B
Explanation:
Explanation:
Total spend = \((4 \times 1800) + (8 \times 2000) = 23200\). Total income = \(23200 + 5600 = 28800\). Monthly = \(28800 / 12 = 2400\).
25.
The average age of 30 students is 9 years. If the teacher is included, the average becomes 10 years. What is the teacher's age?
View Answer
Answer: Option B
Explanation:
Explanation:
Total age with teacher = \(31 \times 10 = 310\). Total age without teacher = \(30 \times 9 = 270\). Teacher = \(310 - 270 = 40\) years.