Mathematics/General Ability MCQs
Topic Notes: Mathematics/General Ability
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
331
The average salary per head of all workers in a workshop is Rs. 850. If the average salary of 7 technicians is Rs. 1000 and the rest earn Rs. 780 on average, how many workers are there in total?
Answer:
20
Let total workers = n. Total salary = 850n. Salary of technicians = 7 × 1000 = 7000. Remaining salary = 780(n − 7). Equation: 7000 + 780(n − 7) = 850n → solving gives n = 20.
332
The average earning of a mechanic for the first four days of a week is Rs. 18 and for the last four days is Rs. 22. If he earns Rs. 20 on the fourth day, what is his average earning for the whole week?
Answer:
Rs. 20
First 4 days total = 4 × 18 = 72. Last 4 days total = 4 × 22 = 88. Combined = 160 but the 4th day is counted twice, so subtract 20 → 140. Average for 7 days = 140 ÷ 7 = 20.
333
The average of numbers 0.64204, 0.64203, 0.64202, and 0.64201 is:
Answer:
0.642025
Sum = 0.64204 + 0.64203 + 0.64202 + 0.64201 = 2.5681. Dividing by 4 gives the average = 2.5681 ÷ 4 = 0.642025.
334
The average of 30 results is 20 and the average of another 20 results is 30. What is the average of all the results together?
Answer:
24
Sum of first 30 results = 30 × 20 = 600. Sum of next 20 results = 20 × 30 = 600. Total sum = 1200 and total number of results = 50. Average = 1200 ÷ 50 = 24.
335
The average age of 24 students is 10. When the teacher's age is included, the average becomes 11. What is the teacher's age?
Answer:
35 years
Total age of students = 24 × 10 = 240. Including teacher: 25 × 11 = 275. Teacher's age = 275 − 240 = 35.
336
The average of five results is 46 and the average of the first four is 45. What is the fifth result?
Answer:
50
Sum of 5 results = 5 × 46 = 230. Sum of first four = 4 × 45 = 180. Fifth result = 230 − 180 = 50.
337
The average of odd numbers up to 100 is:
Answer:
50
Odd numbers up to 100 run from 1 to 99. Average = (first + last) ÷ 2 = (1 + 99) ÷ 2 = 50.
338
The average of the first nine multiples of 3 is:
Answer:
15.0
First nine multiples of 3 range from 3 to 27. Average of evenly spaced numbers = (first + last) ÷ 2 = (3 + 27) ÷ 2 = 15.
339
If a, b, c, d, e are five consecutive odd numbers, what is their average?
Answer:
(a + 4)
Five consecutive odd numbers can be written as a, a+2, a+4, a+6, a+8. Their sum is 5a + 20. Dividing by 5 gives the average = a + 4.
340
The average height of 30 girls in a class of 40 is 160 cm and that of the remaining girls is 156 cm. What is the average height of the entire class?
Answer:
159 cm
Total height of first group = 30 × 160 = 4800. Total height of remaining 10 = 10 × 156 = 1560. Combined height = 6360. Average = 6360 ÷ 40 = 159 cm.