Sequences and Series
The minimum value of the sum of real numbers a−5+a−4+3a−3,1,a8 and a10 with a>0 is
The sum of the first four terms of an A.P. is 56. The sum of the last four terms is 112. If its first term is 11, then find the number of terms.
A person writes a letter to four of his friends. He asks each one of them to copy the letter and mail to four different persons with instruction that they move the chain similarly. Assuming that the chain is not broken and that it costs 0 paise to mail one letter. Find the amount spend on the postage when 8th set of letter is mailed.
Ramkali saved Rs 5 in the first week of a year and then increased her weekly savings by Rs 1.75. If in the nth week, her weekly savings become Rs 20.75, find n.
Sum of the first p, q and r terms of an A.P are a, b and c, respectively.Prove that pa(q−r)+qb(r−p)+rc(p−q)=0
A mail starts repaying a loan as first instalment of Rs. 100. If he increases the instalment by Rs 5 every month, what amount he will pay in the 30thinstalment?