Let a1,a2,a3,....,a10 be in G.P. with a1>0 for i=1,2,...10 and S be the set of pairs (r,k),rk∈N (the set of natural numbers) for which
∣∣
∣
∣∣logear1ak2logear2ak3logear3ak4logear4ak5logear5ak6logear6ak7logear7ak8logear8ak9logear9ak10∣∣
∣
∣∣=0
Then the number of elements in S, is :