On a particular day, Rose's teacher read the register and realized there were twice as many girls as boys present on that day. The class has 250 students, and all the 140 girls were present. If all the absent students were boys, how many boys were absent that day?
Thoughts? Step-by-step reasoning:
If there were twice as many girls as boys present that day, then the number of boys is 140 girls / 2 girls / boy = 70 boys. The total number of students present that day is 140 girls + 70 boys = 210 students. If the class has 250 students, then the number of boys absent is 250 students - 210 students = 40 boys.
Thus, the answer is 40.