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 50 paise to mail one letter. Find the amount spend on the postage when 8th set of letter is mailed.

Dipesh writes letters to four of his friends. He asks each of them to copy the letter and mail to four different persons with the request that they continue the chain similarly. Assuming that the chain is not broken and that it costs 25 paise to mail one letter, find the total money spent on postage till the 8th set of letters is mailed.

Ram and Ali have been fast friends since childhood. Ali neglected studies and now has no means to earn money other than a channel whereas Ram has become an engineer. Now both are working in the same factory. Ali uses camel to transport the load within the factory. Due to low salary and degradation in health of camel, Ali becomes worried and meets his friend Ram and discusses his problems. Ram collected some data and with some assumptions concluded the following: i. The load used in each trip is 1000kg and has friction coefficient mu_k=0.1 and mu_s=0.2 . ii. Mass of camel is 500kg . iii. Load is accelerated for first 50m with constant acceleration, then it is pulled at a constant speed of 5ms^-1 for 2km and at last stopped with constant retardation in 50m . iv. From biological data, the rate of consumption of energy of camel can be expressed as P=18xx10^3v+10^4Js^-1 where P is the power and v is the velocity of the camel. After calculations on different issues, Ram suggested proper food, speed of camel, etc. to his friend. For the welfare of Ali, Ram wrote a letter to the management to increase his salary. (Assuming that the camel exerts a horizontal force on the load): The ratio of the energy consumed by the camel during uniform motion for the two cases when it moves with speed 5ms^-1 to the case when it moves with 10ms^-1

Statement 1: There are 4 addressed envelopes and 4 letters for each one of them. The probability that no letter is mailed in its correct envelops is 3/8. Statement 2: The probability that all letters are not mailed in their correct envelope is 23/24.