Problema Solution
During a 1 hour television program, there were 22 commercials. Some commercials were 15 second and some were 30 seconds long. Find the number of 15-second commercials and the number of 30-second commercials if the total playing time for commercials was 9.5 minute.
Answer provided by our tutors
x + y = 22
15x + 30(22-x) = 570
15x = 660 - 570 = 90
x = 6 = the number of 15-second commercials
y = 16 = the number of 30-second commercials