How many girls joined in the trip?

Now, you want me to tell you another story. Right? OK. Here’s another one. Seven young students, four boys and three girls, after traveling on foot for five hours, arrived at the forest where they were going to stay for several days. Now they sat down and took a rest. All of them felt tired, hot and hungry, so they decided to eat something first. They washed their hands in the river and quickly sat down and ate up all food that they had brought with them. Now they were all ready to start. "Oh, no!" cried one of the girls. "What’s the matter?" asked the other children. "We’ve forgotten to bring the food!"