http://i146.photobucket.com/albums/r...ouis/prob3.jpg

I have started in this direction but i was told it was wrong:

A bar (overset 1)20:20l(with bar above last 20) = (i/δ) A20:20l (with bar above last 20)

A bar (overset 1)20:20l(with bar above last 20) = .02 (given)

i = .1 (given)

A20:20l (with bar above last 20) = .32 (given)

A bar (overset 1)40:30l(with bar above 30)= .25

trying to find: A bar (overset 1)20:50l(with bar above 50)= ?

so, .02 = (.1/δ)*.32

.0625 = .1/δ

δ = 1.6