This handy little diagram can help you quickly calculate for the unknown variable.
The horizontal line means divide – ie D divided by S or D divided by T
The vertical line means multiply – ie S times T
Just insert the values you have and solve for the unknown.
Eg if your Distance = 5nm and your time to cover it was 2.5 hrs then D/T = S [5/2.5 = 2 kts]
If your Speed = 3kts and your Distance is 7 nm then D/S = T [7/3=2.3 hrs]
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