Q1. In a group of 68 students, each student is registered for at least one of three classes - History, Math and English. Twenty-five students are registered for History, twenty-five students are registered for Math, and thirty-four students are registered for English. If only three students are registered for all three classes, how many students are registered for exactly two classes?
Q2. At a certain dealership, every car on the lot has at least one of three modest options: windows, brakes and radio. 40 cars have windows, 30 cars have brakes, and 50 cars have a radio. 21 cars have B&R, 13 cars have B&W and 17 cars have W&R. If 11 cars have all 3 options, what is the total number of cars on the lot?
For Q1, we are applying the following equation for 3 overlapping sets:
Total = H + M + E - (HM + ME + HE) - 2(HME)
68 = 25 + 25 + 34 - Sum - 6
Sum = 10
While for Q2, we are applying a different equation for 3 overlapping sets:
Total = B + W + R - (BR + BW + WR) + BWR
Total = 40 + 30 + 50 -21 - 13 - 17 + 11
Total = 80
Please explain the different scenarios/equations and when they must be applied...
Thanks,
Adi
Q2. At a certain dealership, every car on the lot has at least one of three modest options: windows, brakes and radio. 40 cars have windows, 30 cars have brakes, and 50 cars have a radio. 21 cars have B&R, 13 cars have B&W and 17 cars have W&R. If 11 cars have all 3 options, what is the total number of cars on the lot?
For Q1, we are applying the following equation for 3 overlapping sets:
Total = H + M + E - (HM + ME + HE) - 2(HME)
68 = 25 + 25 + 34 - Sum - 6
Sum = 10
While for Q2, we are applying a different equation for 3 overlapping sets:
Total = B + W + R - (BR + BW + WR) + BWR
Total = 40 + 30 + 50 -21 - 13 - 17 + 11
Total = 80
Please explain the different scenarios/equations and when they must be applied...
Thanks,
Adi
