If a varies directly as b and a=4 when b=20, what is the value of a when b=8?

If b equals 8 then a would equal 1.6

The answer is $5,000.73.
Explanation: If one Canadian dollar bill is $1.00 and a Trinidad’s $1.00 is $2.73 then that means if you wanna convert it you have to double the amount including the €73 and you have 2,500 you need to double the amount then add the remaining €73.