if the sum of first 5 terms of a G.P. is 155, sum of last 5 terms is 39680,first term is 5 and last term is 20480. find the number of terms of the sequence.
to make an open fish tank a glass sheet of
2mm gauge is used .the outer length
,breadth and height are 60.4 , 40.4,
40.2 respectively .how much maximum
volume of water will be contained in it ?