Why 3 test in Kotlin 25 gave me a error?

Question

fun shippingCost(amount: Double, international: Boolean): Double {
if(international == false && amount >= 75){
return (amount % amount)
}
if(international == false && amount < 75){
return (amount * 10 / 100)
}
else{
return (amount * 15 / 100)
}
}
fun main(args: Array<String>) {
val total = readLine()!!.toDouble()
val international = readLine()!!.toBoolean()
println(shippingCost(total, international))
}

Answer 1

For international orders, there is a 15% shipping fee, with a maximum of $50. This means that the maximum shipping fee for an international order is $50.
So, you should return 50.0 if amount *0.15 is greater than 50$.