You might need: Calculator

Problem

A young sumo wrestler decided to go on a special high-protein diet to gain weight rapidly. He started at 90 kilograms and gained weight at a constant rate. After 8 months, he weighed 138 kilograms.
Let W, left parenthesis, t, right parenthesis denote the sumo wrestler's weight W (measured in kilograms) as a function of time t (measured in months).
Write the function's formula.
W, left parenthesis, t, right parenthesis, equals
Do 4 problems