ROC conversion from % Gradient

In order to calculate a required ROC from a % Gradient, use the following formula:

Rate of Climb = Gradient [%] x Groundspeed [kt]


In the chart it says you need to keep a 4% Gradient until 3000 ft. Assuming you have a Groundspeed of 150 kts, the required ROC would be:

ROC = 4 x 150 kts = 600 feet per minute