Rise over run. Difference in y values is rise. 4.25 -6 is -1.75. Run s difference in x values. 12.5 -7 is 5. Divide -1.75/5 to get -0.35 As a faction thats -7/20
Base elevation is 1250 ft rate is 30 per minute 30m so, h = 1250 - 30m as an inclusion, 30 ft per minute is also like 0.5 per second like 1250 - 0.5s 1250/30 means it would be about 42 minutes once it touches the ground.