Q178. Of the 300 subjects who participated in an experiment using virtual-reality therapy to reduce their fear of heights, 40% experienced sweaty palms, 30% experience vomiting, and 75% dizziness. If all of the subjects experienced at least one of these effects and 35% of the subjects experienced exactly 2 of these effects, how many of the subjects experienced only one of these effects?
d) 180 - Correct answer
Below is the OG's solution, but I don't really understand how they get there....Can you help?
They say: a+35%*100+c=300 -> (i) a+c = 195
Sweaty: 40% of 300=120
Vomiting=90
Dizziness=225
Each participant who experienced only one of the effects is counted exactly once, each participant who experienced exactly two of the effects is counted exactly twice and each participant who experienced all three of the effects is counted exactly 3 times. Therefore, a+2b+3c = 120 + 90 + 225 = 435. Using b=105, it follows that (ii) a +3c=225. Then adds equations (i) and (ii)
d) 180 - Correct answer
Below is the OG's solution, but I don't really understand how they get there....Can you help?
They say: a+35%*100+c=300 -> (i) a+c = 195
Sweaty: 40% of 300=120
Vomiting=90
Dizziness=225
Each participant who experienced only one of the effects is counted exactly once, each participant who experienced exactly two of the effects is counted exactly twice and each participant who experienced all three of the effects is counted exactly 3 times. Therefore, a+2b+3c = 120 + 90 + 225 = 435. Using b=105, it follows that (ii) a +3c=225. Then adds equations (i) and (ii)
