Answer: Equal amounts of the wrong drink in each – Crucially, the two cups have equal amounts of liquid before and after the mixing. Without needing to do the algebra you can argue that if one cup contains 90% tea and 10% coffee, the other 10% of tea must be mixed with the other 90% of coffee because the percentages of each drink must add to 100.
“You progress further on your journey”
Alice and Bob have a 100-metre race. Alice crosses the line when Bob has only reached the 90m mark. They race again but with Alice starting 10m behind Bob. Who will win?