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Six numbers are arranged in decreasing order. The average of the first five numbers is 30 and the average of the last five numbers is 25. The difference of the first and the last numbers is :
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- 20
- 25
- 5
- 30
Correct Option: B
Let us assume that six numbers are p, q, r, s, t, u.
According to the given question, Numbers are in decreasing order :
p > q > r > s > t > u
Again according to the question,
p + q + r + s + t = 5 × 30
⇒ p + q + r + s + t = 150 --- (i)
q + r + s + t + u = 5 × 25
⇒ q + r + s + t + u = 125 --- (ii)
By equation (i) – (ii)
p – u = 150 – 125 = 25
