Respuesta :
Answer:
The answer is 45 minutes.
Step-by-step explanation:
30 divided by 10 is 3. So it's 3 minutes per book. 3 multiplied by 15 is 45.
The answer is 45 minutes because 30 divided by 10 is 3 which means rock reads 1 book every 3 minutes and 3 times 15 is 45