I notice that sites such as Google Finance quote the pound to dollar
conversion rates in the form GBP/USD = 1.4784.
I would read this as "GBP per USD = 1.4784" or equivalently "1.4784 GBP per
USD" which is obviously the wrong way round.

When we quote speeds for example we say mph (or m/h) = 50 - meaning there are 50 miles for each hour. It's the same with all other rates in the physical sciences. And to calculate the rate of a/b (i.e. a per b) you just divide the number of a's by the equivalent number of b's.

So why do economists use an illogical and misleading convention?

Thanks Thomas

When we quote speeds for example we say mph (or m/h) = 50 - meaning there are 50 miles for each hour. It's the same with all other rates in the physical sciences. And to calculate the rate of a/b (i.e. a per b) you just divide the number of a's by the equivalent number of b's.

So why do economists use an illogical and misleading convention?

Thanks Thomas