A survey of 285 adults found that during the last year, 75 traveled by plane but not by train, 55 traveled by train but not by plane, 30 traveled by bus but not by plane or by train, 70 traveled by bus and plane, 35 traveled by all three, and 215 traveled by plane or train. How many did not travel by any of these modes of transportation

40

Step-by-step explanation:

Given that

Total number of adults, U = 285

Number of plane travellers, P = 75

Number of train travellers, T = 55

To find the number of people that didn't travel by any means of transportation listed in the question, then we say

Total number of adults minus number people who traveled by plane or train minus number of people who traveled by bus but not by plane or train.

This means that number of people who didn't travel by any of the three means of transportation, N =

N = U - pt - b

N = 285 - 215 - 30

N = 40

Therefore, the total number needed is 40

step-by-step explanation: