You have to use the equation q=mcΔT and solve for c to get c=q/mΔT q=the amount of energy absorbed or released (in this case 150J) m= the mass of the sample (in this case 10g) c=the specific heat capacity of the sample ΔT=the change in temperature (in this case 115°C) when you plug everything in you should get 0.1304J/g°C
I hope this helps. Let me know if anything is unclear.