Question

A rope is cut into 10 pieces whose lengths are in geometrical progression
measured 20metres, 18 metres, 16.2 metres in decreasing order.
( i ) find the length of the rope to the nearest metres [ 3 marks]
( ii ) Find the length of the last piece that is more than 10 metres
long
[4 marks]

Answer 1

i) Length of rope= Sum of GP
=>\[\frac{ a \left( 1-r ^{n} \right) }{1-r }\]
=>
=> 20(1-0.05)*10
=> 200*0.95
=> 190