A man bought 4 books for ₹50 each, 5 books for ₹60 each and 6 books for ₹70 each. The average cost of a book for the man is (round up to two decimal places):

The correct answer is ₹61.33.

Step-by-step Solution:

To find the average cost of a book, we need to calculate the total cost of all the books purchased and divide it by the total number of books.

Step 1: Calculate the total cost of each type of book.

• Cost of 4 books at ₹50 each = 4 × 50 = ₹200

• Cost of 5 books at ₹60 each = 5 × 60 = ₹300

• Cost of 6 books at ₹70 each = 6 × 70 = ₹420

Step 2: Find the total cost of all the books.

Total Cost = ₹200 + ₹300 + ₹420 = ₹920

Step 3: Find the total number of books.

Total Books = 4 + 5 + 6 = 15 books

Step 4: Calculate the average cost per book.

The formula for average cost is:

$\text{Average Cost}=\frac{\text{Total Cost}}{\text{Total Number of Books}}$

Substituting the values:

$\text{Average Cost}=\frac{920}{15}=\mathrm{61.3333...}$

Rounding off to two decimal places, we get ₹61.33.