Electromagnetic Induction

A solenoid of length \(60 \mathrm{~cm}\) with 15 turns per \(\mathrm{cm}\) and area of cross-section \(4 \times 10^{-3} \mathrm{~m}^2\) completely surrounds another co-axial solenoid of same length and area of cross-section \(2 \times 10^{-3} \mathrm{~m}^2\) with 40 turns per \(\mathrm{cm}\). Mutual inductance of the system is