Let a₁, a₂, ...... a₄₀ be in AP and h₁, h₂, ..... h₁₀ be in HP. If a₁ = h₁ = 2 and a₁₀ = h₁₀ = 3, then a₄h₇ is

Let a₁, a₂, a₃ .... be a harmonic progression with a₁ = 5 and a₂₀ = 25. The least positive integer n for which a_n < 0, is

In a sequence of 21 terms, the first 11 terms are in AP with common difference 2 and the last 11 terms are in GP with common ratio 2. If the middle term of AP be equal to the middle term of the GP, then the middle term of the entire sequence is

If a + 2b + 3c = 12, (a, b, c $$\in$$R⁺), then the maximum value of ab²c³ is