For Q using steady state concept Rate of appearance of Q= rate of disappearance of Q K1[P]=K2[Q] Number of nuclei of Q=
k1
k2
×no. of nuclei of P=
10∕60
1000
×6×1023=1020 For R, since rate constant is very high for second step than first step Number of nuclei of R= Number of nuclei of P disintegrated =6×1023