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Answered by
72
Given that
.
.
.
.
So,
It implies,
Since, each element is used 10 times,
So,
Also,
.
.
.
.
So,
It implies,
Since, each element is used 9 times.
From equation (1) and equation (2), we get
Answered by
64
ANSWER:
Given:
- A₁, A₂. . . . . A₃₀ are 30 sets with 5 elements each.
- B₁, B₂. . . . . B
are n sets with 3 elements each.
- Each element of S∈10 elements of A
's and 9 elements of B
's
To Find:
- Value of n
Solution:
We are given that, A₁, A₂. . . . . A₃₀ all contain 5 elements each.
So,
⇒ Total elements in A₁, A₂. . . . . A₃₀ = 30 * 5 = 150elements.
As each element of S belongs to 10 of A's,
⇒ 10 × S = 150
⇒ S = 15 ------(1)
Now,
We are given that, B₁, B₂. . . . . B all contain 3 elements each.
So,
⇒ Total elements in B₁, B₂. . . . . B = n * 3 = 3n elements.
As each element of S belongs to 9 of B's,
⇒ 9 × S = 3n
From (1),
⇒ 9 × 15 = 3n
⇒ n = 135/3
⇒ n = 45
Therefore, the correct option is c) 45.
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