Pharmacological products must specify recommended dosages for adults and children. Two formulas for modification of adult dosages levels for young children are

Cowling's rule: y = (1 / 24) (t + 1)a

Friend's rule: y = (2 / 25)ta

where a denotes the adult dose (in milligrams) and t denotes the age of the child (in years).

(a) If a = 100, graph the two linear equations on the same axes for 0 <= t <= 12.

(b) For what age do the two formulas specify the same dosage?