Question

200 wooden balls each of diameter 70 mm are to be painted Find the cost of painting these balls at 10 paise/$c{m}^2$

• A. Rs.3080
• B. Rs.2771
• C. Rs.4000
• D. Rs.7000

Answer 1

The correct option is A Rs.3080

Total surface area of 200 balls of $\frac{35}{10}$ cm radius will be $200\times 4\times \frac{22}{7}\times \frac{35}{10}\times \frac{35}{10}$ mm
The cost will be Rs $\frac{200\times 4\times 22\times 35\times 35}{7\times 10\times 10\times 100}$ which simplifies to Rs 3080