Delta - Wye Transformation of Resistance Network?

Question

1) In the Wheatstone Bridge circuit, R1 & R4 have a resistance of 300 ohms each. R2 & R3 each have a resistance of 150 ohms. The source voltage is 100 volts. What is the current thru to galvanometer if its resistance is 50 ohms?

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http://img177.imageshack.us/img177/5990/wheatstonesb3.jpg

*Please GIVE ME ALL THE STEPS

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2) Use the delta-wye transformation to determine what voltage must be applied to the input terminals of the lattice network of the figure below in order to draw a 2 Ampere current from the source when a 20 ohm load is connected to the output terminals of the network.

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http://img177.imageshack.us/img177/2054/wyedeltakz3.jpg

*Please GIVE ME ALL THE STEPS

Answer 1

Reduce them to their Thevenin's equivalent then apply Ohm's Law.

Answer 2

homework time again eh?