Correct Answer - `2.5 xx 10^13`
Total energy produced/minute `= 48 kJ = 48 xx 10^3 J`
Energy produced/second `= (48 xx 10^3)/(60) J = 0.8 xx 10^3 J`
Energy released/fission `= 3.2 xx 10^-11 J`.
Number of fissions/second `= ("energy produced"//"s")/("energy released"//"fission") = (0.8 xx 10^3)/(3.2 xx 10^-11) = 2.5 xx 10^13`.