A lift has the capacity of 18 adults or 30 children. How many children can board the lift with 12 adults?
Let the capacity of lift be 90x (LCM of 18 and 30).
Capacity of 1 adult = 90x/18 = 5x
Capacity of 1 child = 90x/30 = 3x
With 12 adults, lift is already occupied with 12 × 5x capacity = 60x capacity.
Remaining capacity = 90x - 60x = 30x
Number of children that can board = 30x/3x = 10
The correct option is B.