Here is the thing. I am not totally sure about the formulas because I don't know what they represent, so I will that with you.
But I am going to do is, give you better understanding of how conversion works so you can solve this and many other similar problems.
Lets say you are trying to find the speed of wind with $\frac{m}{s}$ - where m is meter and s is second. You are given a speed 30$\frac{km}{h}$. The way conversion works is you replace the current unit with (KM in our case) with its equivalent with new unit(m in our case). Since 1km = 1000m and 1hour = 60 mins = 60 * 60 seconds our new formula will be like this:
$$30\frac{km}{h} = 30*\frac{1000}{60*60} = 30 * \frac{1000}{3600} = 30* \frac{5}{18} = 8.3 \frac{m}{s}$$
Now all you need to is apply the same logic to your case. If you want to change a day to hour, replace d with 24h. If you are given $2\frac{inch}{Day}$ to get $\frac{mm}{h}$ replace inch with equivalent mm which is 25.4(according to google) and 1 day = 24Hour. So formula will like like this $$2\frac{inch}{Day} = 2*\frac{25.4}{24} \approx 2.1$$