There are 220 people learned of the sale from radio or television
but not the​ newspaper
Step-by-step explanation:
A merchant surveyed 500 people to determine the way they learned
about an upcoming sale
The survey showed that:
To solve this problem by an easy way draw a Venn-diagram represents
the survey
In the attached figure:
There are 3 intersected circles R for radio , T for television and N for
newspaper
Let us fill it by the given
∵ There are 70 learned from all three sources
∴ R ∩ T ∩ N = 70
∴ Write in the common part of R , T and N 70
∵ There are 140 from radio and​ television
- Subtract 70 from 140 to get R ∩ T only
∴ Write in the common part of R and T not in N 140 - 70 = 70
∵ There are 130 learned from radio and​ newspaper
- Subtract 70 from 130 to get R ∩ N only
∴ Write in the common part of R and N not in T 130 - 70 = 60
∵ There are 120 learned from television and​ newspaper
- Subtract 70 from 120 to get T ∩ N only
∴ Write in the common part of T and N not in R 120 - 70 = 50
∵ There are 290 learned about the sale from the​ radio
∴ There are 290 - 70 - 70 - 60 = 90 learned from the radio only
∵ There are 250 learned about the sale from the​ television
∴ There are 250 - 70 - 70 - 50 = 60 learned from the television only
∵ There are 250 learned about the sale from the​ newspaper
∴ There are 250 - 70 - 60 - 50 = 70 learned from the newspaper only
∵ There are 500 people in the survey
∵ There are 90 + 70 + 60 + 50 + 70 + 60 + 70 = 470 in R, T and N
∴ There are 500 - 470 = 30 not learned from the three sources
∴ Write 30 in the region outside the circles
∵ We need to find the people learned from radio or television but
  not the​ newspaper
- Add all the numbers in circles R and T but not in circle N
∵ 90 + 70 + 60 = 220
∴ There are 220 people learned of the sale from radio or television
  but not the​ newspaper
There are 220 people learned of the sale from radio or television
but not the​ newspaper
Learn more:
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