Q3.

Simplify: \(9^2 + \sqrt{4^2} - 7\sqrt{16} - 7\).

Q4.

A, B, and C can complete a work in 10, 12, and 15 days, respectively. A and B work together for 3 days, after which A withdraws. B and C then work together. Find the number of days required by B and C to complete the remaining work.

Q5.

A hollow spherical shell is made of a metal of density 39 g/cm³. Its internal and external radii are 12 cm and 13 cm, respectively. What is the weight (in kg) of the shell?

 (Use \(\pi = \frac{22}{7}\) and Density = Mass/Volume)