Let a1,a2,a3,a4,a5 be such that a1,a2,a3 are in A.P... a2,a3,a4 are in G.P and a3,a4,a5 are in H.P.then a1,a3,a5 are in..

Did you attempt it?

Yes but its useless to show it... :p.. can u please solve?

Nope, it's not useless to show it. Someone might actually point out where you went wrong.

Actually I've done it now :D
Let the 5 nos are 1,2,3,9/2,9. here a1a2a3 are in a.p ,a2a3a4 are in g.p ,a3a4a5 are in h.p. so a1a3a5 are in 1,3,9 in g.p... ye it wasn't USELESS ;P

That's why we always encourage that people post their attempts :)

Sometimes, even if you don't see it, someone else might see it ;)