Given: the sequences are 2, 4, 8,16, 32 and 128, 32, 8, 2,

The Required answer is: 2 × 128 + 4 × 32 + 8 × 8 + 16 × 2 + 32 ×

⇒ 64 × [4 + 2 + 1 + + ]

Here the terms are in G.P

Where a = 4, r = and n = 5

The Sum of terms in G.P. is given by:

∴ S = 64 ×

⇒ S = 64 ×

⇒ S = 64 ×

⇒ S = 2 ×

⇒ S = = 496

∴ The required answer is 496.