Same pattern as Bus passengers — boarding, alighting, doubling. New numbers, new story. Try each one on paper, then check the working below — or watch it drawn out, the same way the problem above is.
Question 1
There were some passengers in a cable car. At the first station, 15 passengers boarded and 6 got off. At the second station, the number of passengers doubled. There were then 50 passengers. How many passengers were in the cable car before the first station?
Work it out on paper, then check below. ▶ See the working
Question 2
Ravi had some marbles in a jar. He added 20 marbles and removed 8 marbles. Then a magic trick doubled the number of marbles in the jar. There were then 70 marbles. How many marbles were in the jar before he added or removed any?
Work it out on paper, then check below. ▶ See the working
Question 3
Mei had some stickers in her sticker book. She traded with a friend, receiving 18 stickers and giving away 7 stickers. Then a bonus pack doubled the number of stickers in her book. She then had 60 stickers. How many stickers did she have before she traded with her friend?
Work it out on paper, then check below. ▶ See the working