Combining Resistors for 5W Dissipation in 10 Ohms

[miew]

Homework Statement

You are given a number of 10 resistors, each capable of dissipating only 1.0 W without being
destroyed. What is the minimum number of such resistors that you need to combine in series or
in parallel to make a 10 resistor that is capable of dissipating at least 5.0 W?

Homework Equations

The Attempt at a Solution

I don't understand the problem. I can't see how the final resistance can be 10 if there is more than one resistor. But at the same time I don't get how the power can be 5 with just one..

Help please, we haven't really seen this in class.

 

[ehild]

Start with 4 resistors. What is the resultant resistance of two parallel resistors each of resistance R? And what happens if you connect two such pairs in series?

ehild

 

[miew]

OKay, so i got the resistance (I was doing wrong calculations) but I don;t get the power to be 5 but 4 W...

 

[ehild]

Try connecting more resistors. You need 5 at least.ehild

 

[miew]

I got it now ! thank you :)