For T = 89.5 degrees C: E(t) = 1100(90 - 89.5) + 520(90 - 89.5)^2= 1100(0.5) + 520(0.5)^2= 550 + 130= 680 m For T = 90 degrees C: E(t) = 1100(90 - 90) + 520(90 - 90)^2= 0 + 0= 0 m (meaning that boiling point is 90 degrees C at ground level)
First you subtract 242 from 1250 which gives you 1080. Then you divide it by 8 which gives you 126. Multiply this value by 3 and this shows that Haryati received $378. Hope this is helpful.