Need some help regarding Cessna 172 performance

[9 lives]

Your result will be "close enough" if you average the values for each at 10 and 20C. So, ground roll 1010 and 1090; 1010 + 1090 = 2100 / 2 = 1050 feet ground roll. I'll let you do the climb to 50 feet distance calculation using the same method.