There are 500 children in a village. 49% of children watch Doraemon and 53% of children watch Sinchain and 62% of children watch Tom & Jerry. 27% of children watch both Doraemon and Sinchain. 29% of children watch both Sinchain and Tom & Jerry. 28% of children watch both Doraemon and Tom & Jerry. 5% of children don’t watch any cartoons. Find the number of children who watch at least two of the given cartoons.
There are 500 children in a village. 49% of children watch Doraemon and 53% of children watch Sinchain and 62% of children watch Tom & Jerry. 27% of children watch both Doraemon and Sinchain. 29% of children watch both Sinchain and Tom & Jerry. 28% of children watch both Doraemon and Tom & Jerry. 5% of children don’t watch any cartoons. Find the number of children who watch at least two of the given cartoons. Correct Answer 270
Formula used:
Total number of children who watch all cartoons
⇒ n(A ∪ B ∪ C) = n(A) + n (B) + n (C) - n (A ∩ B) - n (B ∩ C) - n (C ∩ A) + n (A ∩ B ∩ C)
Where n(A) = number of elements in set A.
Watch at least two cartoons = n(A ∩ B) + n(B ∩ C) + n(C ∩ A) - 2 × n(A ∩ B ∩ C)
Given:
Total number of children in village = 500
Who watch Doraemon = 49%
Who watches Sinchain = 53%
Who watch Tom & Jerry = 62%
Who watches both Doraemon and Sinchain = 27%
Who watches both Sinchain and Tom & Jerry = 29%
Who watches both Doraemon and Tom & Jerry = 28%
Who don’t watch any cartoons = 5%
Calculation:
|
A |
Doraemon |
|
B |
Sinchain |
|
C |
Tom & Jerry |
Total number of children in village = 500
Total number of children who watch Doraemon = 49% of 500
⇒ (49 / 100) × 500 = 245
Total number of children who watch Sinchain = 53% of 500
⇒ (53 / 100) × 500 = 265
Total number of children who watch Tom & Jerry = 62% of 500
⇒ (62 / 100) × 500 = 310
Total number of children who watch both Doraemon and Sinchain = 27% of 500
⇒ (27 / 100) × 500 = 135
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Total number of children who watch both Sinchain and Tom & Jerry = 29% of 500
⇒ (29 / 100) × 500 = 145
Total number of children who watch both Doraemon and Tom & Jerry = 28% of 500
⇒ (28 / 100) × 500 = 140
Total number of children who don’t watch any cartoons = 5% of 500
⇒ (5 / 100) × 500 = 25
Total children who watch cartoons = 500 - 25 = 475
Total number of children who watch all cartoons
By formula,
⇒ n(A ∪ B ∪ C) = n(A) + n (B) + n (C) - n(A ∩ B) - n(B ∩ C) - n(C ∩ A) + n(A ∩ B ∩ C)
⇒ 475 = 245 + 265 + 310 - 135 - 145 - 140 + n (A ∩ B ∩ C)
⇒ n(A ∩ B ∩ C) = 475 - 400 = 75
Now number of children who watch at least two cartoons
⇒ n(A ∩ B) + n(B ∩ C) + n(C ∩ A) - 2 × n(A ∩ B ∩ C)
⇒ 135 + 145 + 140 - 2 × 75
⇒ 420 - 150 = 270
∴ The total number of children who watch at least two cartoons is 270.
Alternate method:
By percentage:
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Let the total of children in the village be 100%
Children who watch Doraemon = 49%
Children who watch Sinchain = 53%
Children who watch Tom & Jerry = 62%
Since 5% of children don’t watch any cartoons.
Total children who watch cartoons = 100 - 5 = 95%
Who watch both Doraemon and Sinchan = 27%
Who watch both Sinchan and Tom & Jerry = 29%
Who watch both Doraemon and Tom & Jerry = 28%
Total number of children who watch all cartoons
⇒ 95 - 49 - 53 - 62 + 27 + 29 + 28 = 15%
Now number of children who watch at least two cartoons
⇒ 27 + 29 + 28 - 2 × 15 = 54%
⇒ 54% of 500
⇒ (54 / 100) × 500 = 270
∴ The total number of children who watch at least two cartoons is 270.