walking with 5 / 4 of my usual speed , i miss the bus by 5 minutes . what is my usual time ?
"speed ratio = 1 : 5 / 4 = 4 : 5 time ratio = 5 : 4 1 - - - - - - - - 5 4 - - - - - - - - - ? è 20 answer : c"
multiply(divide(const_3.0, divide(4, 5)), 4)