The equation yˆ=0.35x+62.94 models the glucose level, in mg/dL , where x is the age of a human male.
In the question the approximate age of the male is given and by putting the age of the male in the equation we can reach at the level of the glucose.
It is given that , the age of the male is 40 years
So the level of glucose is 0.35 * 40 + 62.94 = 14 + 62.94 = 76.94 mg/dL