Web(viii) – 26, – 24, – 22, …. to 36 terms Solution: In an A.P., if the first term = a, common difference = d, and if there are n terms. Then, the sum of n terms is given by (i) Given A.P.is 50, 46, 42 to 10 term. First term (a) = 50 Common difference (d) = 46 – 50 = – 4 n th term (n) = 10 = 5 {100 – 9.4} = 5 {100 – 36} = 5 × 64 ∴ S 10 = 320 WebSolution The correct option is B 19 Given that AP is 27, 24, 21 … a = 27; d = 24 - 27 = -3 Sn = n 2(2a+(n−1)d) Since the sum is 0 ⇒ n 2[2×27+(n−1)(−3)] =0 ⇒ n(54−3n+3) = 0 ⇒ …

How many terms of the A.P: 24, 21, 18……............ must be taken so ...

WebAnswer (1 of 2): How many terms of an AP 27, 24, and 21 should be taken so that their sum is zero? Solution: Sn = 0 = (n/2)[54+(n-1)*(-3)] = n[54+3–3n] = n[57–3n] Since n … Web11 apr. 2024 · And the common difference (d) of the A.P is. ⇒ d = ( 21 − 24) = ( 18 − 21) = − 3. Now we have to find out the number of terms in the A.P if the sum of an A.P is 78. As … incantation 2022 bt

Find The Sum Of 21 And 15 - QnA

Web5 apr. 2024 · number of terms in an. A P = n 2 [ 2 a + ( n − 1) d] . Complete step-by-step answer: Series of numbers given is 21, 18, 15 …. Here in this series of AP first term is 21. We can calculate the common difference by subtracting either 21 from 18 or 18 from 15. d = 18 − 21 = 15 − 18 = − 3. So, the common difference is. WebHow many terms of the A.P; 24,21,18,... must be taken such that their sum is 78 Easy Solution Verified by Toppr Formula, S n= 2n[2a+(n−1)d] Given, a=24,d=21−24=−3,S n=78 78= 2n[2(24)+(n−1)(−3)] 156=n[48−3n+3] 3n 2−51n+156=0 n 2−17n+52=0 (n−13)(n−4)=0 ∴n=4,13 Was this answer helpful? 0 0 Similar questions WebHow many terms of the AP:24,21,18.... must be taken so that their sum is 78 ? Hard Solution Verified by Toppr Given: 24,21,18,... are in A.P a=24,d=21−24=−3 Sum = 2n[2a+(n−1)d] ⇒78= 2n[2×24+(n−1)(−3)] ⇒156=n[48−3n+3] ⇒156=n[51−3n] ⇒3n 2−51n+156=0 ⇒3n 2−12n−39n+156=0 ⇒3n(n−4)−39(n−4)=0 ⇒(n−4)(3n−39)=0 ∴n=4,n= … incantation 107 church street whitby