A + B + C = 3 × 45 = 135. A + B = 80 and B + C = 86. Adding the two equations gives A + 2B + C = 166. Substitute A + C = 135 − B → 135 + B = 166 → B = 31 kg.
7462
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?
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.
7463
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?
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.
7464
The average of numbers 0.64204, 0.64203, 0.64202, and 0.64201 is:
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.
7466
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?
