Answer:
3 / 5
Step-by-step explanation:
Book read by Dillon on Monday = 1/5
Book read by Dillon on Tuesday = 2/5
Book read by Dillon on Monday and Tuesday = 1 / 5 + 2 / 5 = 3 / 5
Thus, the fraction of book read by Dillon on Monday and Tuesday is 3 / 5.