It's Valentine's day and lots of couples want to go for a ride on the ferris wheel of love. The wheel of love has ten seats and each seat can fit one couple. Each minute a seat passes by entrance/exit stage. The wheel starts functionung at 8pm for half an hour - do you know how many couples took a ride?
Answers
Answer:
21 couples took a ride.
Step-by-step explanation:
We know that the wheel has ten seats. Also, each minute, a seat passes by the entrance/exit.
Assuming that the wheel starts with a seat at the entrance/exit, then the first couple is already seated. At the end of the first minute, a seat passes by the entrance, so the second couple gets seated and so on.
At the end of the 9th minute, the wheel will be full and 10 couples will have taken a ride.
At the 10th minute, the first couple is at the exit and leaves and the 11th couple sits in. This goes on, a couple gets in as another alights.
At the 20th minute, the 21st couple goes in.
At the 21st minute, one couple alights, but no other couple can go in since that seat won't be back at the exit by the end of 30th minute.
With each stop, the rest of the couples alight without anyone going in.
At the end 21 couples took a ride.