20×3 is 60 and if Sarah counted 45 beats in 20 seconds you'd multiply 45 by 3 so it would be 135.
Answer:
135 beats per minute
Step-by-step explanation:
1.) Find how many times the original time (20 seconds in this scenario) will multiply into 60 seconds.
2.) To find that divde the total to the given information
60 seconds/20 seconds = 3
3.) Multiply 45 seconds (given information) by three and your answer should be correct.
45 x 3 = 135 beats per minute
