IIM Bangalore (BBA-DBE) Algebra > Progression & Series PYQs

What is the sum of the infinite series: $1 - \frac{1}{2} - \frac{1}{4} + \frac{1}{8} - \frac{1}{16} - \frac{1}{32} + \frac{1}{64} - \frac{1}{128} - \frac{1}{256} + \dots?$

If six arithmetic means are inserted between 3 and $\frac{13}{2}$, the ratio of the fifth and the first mean is:

Let $\dfrac{m}{n} = \dfrac{90^2+5 \times 90+4}{90^2+5\times 90+6} \times \dfrac{91^2+5\times 91+4}{91^2+5\times 91+6} \times .......\times \dfrac{98^2+5\times 98+4}{98^2+5\times 98+6}$ where m and n are co-primes. What is the value of $|m - n|$ ?

A boy agrees to work at the rate of one rupee on the first day, two rupees on the second day, four rupees on third day and so on, thus getting on any day twice the amount he received just the day before. How many rupees will the boy earn in all, if he started working on the $5^{th}$ of March and completed the work on the $28^{th}$ of March?

The sum of the first 3 terms of an AP is 6 and that of the last 3 terms is 16. If the AP has 13 terms, what is the Arithmetic mean of the three terms that are exactly at the middle of the progression?