Question

A bike shop stocks road or mountain bikes.In July the ratio of road bikes sold to mountain bikes sold is 3:5.The owner then sells more road bikes but no more mountain bikes, the ratio changes to 2:1.What is the minimum amount of road bikes they could sell?

Answer 1

Start with the minimum number of sales to satisfy the given ratio.
That means, you start with sales of exactly 3 road bikes and 5 mountain bikes.
No more mountain bikes will be sold.
Now start adding one road bike at a time to the road bikes sales number until you get to a ratio of 2:1.