When U.S. citizens travel abroad, they need some understanding of Celsius temperature readings-does one need mittens if the temperature will be 20° C? A quick conversion formula often used by tour guides to give a rough Fahrenheit equivalent for a Celsius reading is
F = 2C + 30 .............. Tourist formula
The exact conversion formula relating these readings is
F = 1.8C + 32 ........... Scientific formula
(a) At what temperatures, Fahrenheit and Celsius, do these formulas agree?
(b) As the Celsius temperature rises above the reading found in part (a), does the tourist formula overestimate or underestimate the actual Fahrenheit temperature? How can you tell this from the two given formulas?