Sum of first 10 terms of a GP is equal to the sum of the first 12 terms in the same GP. Sum of the first 15 terms is 31, what is the third term in the GP?
Sum of first 10 terms is equal to sum of first 12 terms. Sum of first 12 terms = Sum of first 10 terms + 11th term + 12th term 11th term + 12thterm = 0 Let 11thterm = k, common ratio = r 12thterm will be = kr k + kr = 0 k (1 + r) = 0 r = -1 as k cannot be zero Common ratio = -1 Now, sum of 15 terms = a(r - 1)/(r - 1) = 31 ⇒ a(-1 -1)/(-1 -1) = 31 ⇒ a = 31 ∴ Third term = ar = 31 × (-1) = 31
Which monsoon is responsible for rainfall in tamil nadu
The process of burning of trashes, weeds or any organic refuse on the soil surface for the sterilization of nursery beds is known as
Where is the chemical weathering of rocks is most intense ?
Which rootstock is extensively used in North India for citrus propagation?
In jute growing areas the usual alternate crop is .......................?
What is the suitable temperature for nitrifying bacteria?
“Regional Centre of International Rice Research Institute” is recently established in India at:
Arabian Jasmine species is
Which is not the macronutrient?
In which layer of the atmosphere there is a temperature inversion?
