Answer:
10
Step-by-step explanation:
The number of different ways that 2 lights can be chosen from 5 is ₅C₂. Use a calculator or find the value manually:
₅C₂ = 5! / (2! (5−2)!)
₅C₂ = 5! / (2! 3!)
₅C₂ = 5×4×3×2×1 / (2×1 × 3×2×1)
₅C₂ = 5×4 / 2
₅C₂ = 10