Given:
Last year 80 students signed up for a summer trip to Washington, D.C.
This summer 50 students have signed up to go.
To find:
The percent decrease in the number of students.
Solution:
We have,
Students in last year = 80
Students in this year = 50
Now,
[tex]\text{Decrease}\%=\dfrac{\text{Students in last year - Students in this year }}{\text{Students in last year }}\times 100[/tex]
[tex]\text{Decrease}\%=\dfrac{80-50}{80}\times 100[/tex]
[tex]\text{Decrease}\%=\dfrac{30}{80}\times 100[/tex]
[tex]\text{Decrease}\%=\dfrac{3}{8}\times 100[/tex]
[tex]\text{Decrease}\%=37.5[/tex]
Therefore, the correct option is B.