How many terms of the AP:9, 17,25,... must be taken to give a sum oThe first term of an APis 5, the last term is 45 and the sum is 400. Find the number of termsand the common difference.4.f 636?6. The first and the last terms of an AP are 17, and 350 respectively. If the common difference7. Find the sum of first 22 terms of an AP in which d 7 and 22nd term is 149.is 9,how many terms are there and what is their sum?8. Find the sum of first 51 terms of an AP whose second and third terms are 14 and 189. If the sum of first 7 terms of an AP is 49 and that of 17 terms is 289, find the sum of10. Srespectivelyfirst n terms.how that a,, a. .. a, . . form an AP where a, is defined as below:Also find the sum of the first 15 terms in each case.is the sum of first two terms? What is the second term? Similarly, find the 3rd, the 10th and(ii) a, 9-5n11. If the sum of the first n terms of an APis 4n-n, what is the first term (that is S,)? Whatthe nth terms.12. Find the sum of the first 40 positive integers divisible by 6.13. Find the sum of the first 15 multiples of 8.14. Find the sum of the odd numbers between 0 and 50.