Q: In Sweden 85% of all cars are gas cars, and 15% are electric cars. The amount of newcars sold each year are 50% gas cars and 50% electric cars. How long does it take for the Swedish market to be 80% electric cars?

Hi Marie, 

If 50% of new cars sold each year are electric and 50% are gas cars, then you'll never be able to reach a total of 80% electric cars. To achieve 80% you'd need to have a market where more electric cars are sold than gas cars. 

Anonymous B answered best here: It's a trick question!

I'm a bit concerned as this is quite straightforward.

You need to really ramp up your preparation to get ready - most questions are far harder than this!

Note: If the numbers here were different, you would need to setup a breakeven formula.

You need a few more variables to know the answer:
1. How many years do cars last? Is it the same for electric vs. gas? (this way you know how many cars are out there and when they retire, i.e., how the stock will evolve)
2. Should we expect the same breakdown of sales going forward, or do we expect it to remain the same forever?

Of course, if answer for 2. is that the breakdown remains the same, then the answer is “forever”.

My guess is that there was probably something wrong in the prompt.

Anonymous is the dark knight here! If only 50% of all new cars are electric, then you may not ever have 80% total electric cars. 

However, if the lifespan of gas cars is shorter than for electric cars - it may still be possible. As gas cars would retire earlier - thus leaving a higher proportion of electric cars on the roads.

Hi!

Based on the information provided, the answer is forever.

Are you sure there are no additional data available?

Best,

Anto