Answer:
5
Step-by-step explanation:
4x5=20
Every 5 days the number is cut in half. So from 600 mg to day 5, the sample will be 300 mg. Then from day 5 to day 10, the sample will reduce to 150 mg. And finally, from day 10 to day 15, the sample will have reduced to:
75 mg
I hope this Helps!
4 because 40 divid 2= 20 ,40 divid 4=10 ,40 divid 8=5, 40 divid 12=36 remainder 4 remainder =what is left