Question

there are three resistors two of them are each of 5w resistance and the third has 15w resistance .how to obtain an equivalent resistance of 25w and 6w

Answer 1

for obtain 25w resistance
we have to connect all the Resistance in series combination
as
5+5+15=25w

For obtain 6w resistance
we have to connect two resistance of 5w in series and connect resistance of 15w in parallel at its ends.
in series
total resistance=10
now in parallel
1/Rp= 1/10+1/15
=3+2/30 =5/30
Rp=30/5=6w