**ARITHMETIC PROGESSIONS**

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** Formulae used in this chapter:**

In an AP with first term a and common difference d, the nth term(or the general term)is given by an=a+(n-1)d. The sum of the first terms of an AP is given by: If l the last term of the finite AP, say the nth term, then the sum of all terms of the AP .

** EXERCISE 5.1**

Question 1:

In which of the following situations, does the list of numbers involved make as arithmetic progression and why?(i) The taxi fare after each km when the fare is Rs 15 for the first km and Rs 8 for each additional km. Solution: (i) It can be observed thatTaxi fare for 1st km = 15Taxi fare for first 2 km = 15 + 8 = 23Taxi fare for first 3 km = 23 + 8 = 31Taxi fare for first 4 km = 31 + 8 = 39Clearly 15, 23, 31, 39 … forms an A.P. because every term is 8 more than the preceding term.