Answer:
 He will read 72 chapters in 1 day
Step-by-step explanation:
Let us use the ratio method to solve this question
∵ Sam read 6 chapters in 2 hours
∵ He continues to read at this same rate for 1 day
→ We must change the day to hours 
∵ 1 day = 24 hours
∴ We need to find how many chapters he will read in 24 hours
→ Chapter  :  Hour
→   6            :   2
→   x            :   24
→ By using cross multiplication
∵ x × 2 = 6 × 24
∴ 2x = 144
→ Divide both sides by 2
∵  =
 = 
∴ x = 72
∴ He will read 72 chapters in 1 day