Step-by-step explanation:
I guess that means winning a level gives the player twice as many points as for winning the previous level.
if that is the real meaning here, then we have
l1 = 10
l2 = 2×l1 = 2×10 = 20
l3 = 2×l2 = 2×2×l1 = 2×2×10 = 4×10 = 40
ln = 2×ln-1 = l1 × 2^(n-1) = 10 × 2^(n-1)
therefore,
l5 = 10 × 2⁴ = 10 × 16 = 160
