distance(15 min)=30b
Step-by-step explanation
Step 1
Brianna runs in the park every day at the average rate of b meters per minute, it means for every minute she run b meters

then
distance= b (mt)
time=1 minute
rate= b mt per minute.
Step 2
now, 15 minutes she runs double her regular speed ( it is 2b)
time=15 minutes
then
time=15
rate=2b

Step 3
for the other 45 minutes, she runs at her regular rate (b)
time= 45 minutes=0.75 hours
rate=b
distance=distance2
