They brought with them a huge bag of sour gummy worms.
They were at the picnic for 6 hours.
They ate 3 less gummy worms during the second hour than during the first hour.
Each hour after that, they ate 3 fewer gummies than they had eaten the hour before.
During their last hour together, they at the last 5 gummy worms.
Then they went home and told their parents about all the fun they had...and about their stomach aches!
How many gummy worms did the girls eat all together that day?