In order to reduce the material cost, an engineer decides to use a hybrid beam instead of an all-carbon-fiber beam. Both beams have the same overall dimensions with rectangular cross-sections. The hybrid beam contains carbon fibers in the outer layers and E-glass in the core. The costs of the materials are as follows:

Carbon/Epoxy:  $ 20/kg

E-glass/Epoxy:  $1.10/kg

The densities of carbon/epoxy and E-glass/epoxy composites are 1.70 g/cm^3 and 2.10 g/cm^3  respectively. The total carbon fiber thickness in the hybrid beam is equal to the core thickness. Compare the percentage weight penalty and cost savings for the hybrid beam over an all-carbon-fiber beam.