The citizens of a new country proposed a new temperature scale called NTS scale. On the said scale, the ice and steam points of water have temperature 20°T and 50°T respectively. What will the room temperature of 30°c read on the NTS scale?

Answer 1

NTS = m C + b
20 = m * 0 + b
so b = 20 and NTS = m C + 20
50 = m * 100 + 20
so m = 30/100 = 0.30
so
NTS = 0.30 C + 20
if C = 30
NTS = 0.30 * 30 + 20 = 29

Answer 2

By the way, I call that Algebra not geography :)