A survey of 250 adults found that during the last year, 70 traveled by plane but not by train, 70 traveled by train but not by plane, 20 traveled by bus but not by plane or by train, 45 traveled by bus and plane, 20 traveled by all three, and 185 traveled by plane or train. How many did not travel by any of these modes of transportation? and plane, 20 traveled by all three, and 15 traveled by blanc eled by plane but not by train, 95

People who didn't travel by any of these modes = 250 - 205 = 45

Step-by-step explanation:

In the question,

Total number of people included in the survey = 250

People who traveled by plane but not train = 70

i. e.

a + d = 70 ... (1)

People who traveled by Train but not Plane = 70

i. e.

c + e = 70 ... (2)

People who traveled by Bus but not Plane or Train = 20

i. e.

b = 20 ... (3)

People who traveled by Bus and Plane = 45

i. e.

g + d = 45 ... (4)

People who traveled by all three = 20

i. e.

g = 20 ... (5)

People who traveled by Plane or Train = 185

i. e.

a + d + c + e + f + g = 185 ... (6)

So,

People who didn't travel by any of these modes = 250 - (a + b + c + d + e + f + g)

So, on putting from eqn. (3) and (6) we get,

a + b + c + d + e + f + g = 185 + 20 = 205

So,

Therefore, People who didn't travel by any of these modes = 250 - 205 = 45.