Okay great, thank you!

Check the function definition clicking reset:

func bmi(_ weight: Int, _ height: Double) -> String {

Leave it like that, do the casting inside it.

Hello!

I was able to work out the solution in Playgrounds, but seem to keep running into an error when I attempt the test here. The error is as follows:

main.swift:25:56: error: cannot convert value of type 'Int' to expected argument type 'Double'
XCTAssertEqual(solution(weight, height), bmi(weight, height))
^~~~~~
Double( )

Any idea why I am getting this error message?

Thank you!