Question

In an AP:
(i) given a = 5, d = 3, an = 50, find n and Sn.
(ii) given a = 7, a13
7, a13 = 35, find d and S13.
(iii) given a 12 = 37, d = 3, find a and S12.
(iv) given a3 = 15, S10 = 125, find d and alo.
(v) given d = 5, S9 = 75, find a and ag.
- On find nan an.​

Answer 1

Answer:

hope it's helpfull dear friend

Answer 2

Step-by-step explanation:

i) to find: n=?

an= a+(n-1)d

50 = 5+(n-1)3

50=5+3n-3

50=5-3+3n

50=2+3n

50-2=3n

48=3n

n=48/3

n=16

to find: Sn = S16= ?

Sn = n/2[2a + (n-1)d]

S16= 16/2 [2(5) + (16 - 1)3]

= 8[10 + 15 × 3]

= 8[10 + 45]

= 8 × 55

=440

S16 = 440

ii) ur question is not understandable

iii) to find: a = ?

an = a + (n-1)d

a12 = a + (12 - 1)3

37 = a + 11 × 3

37 = a + 33

37 - 33 = a

a = 4

to find : S12=?

Sn = n/2 [2a + (n - 1)d]

S12 = 12/2 [2(4) + (12 - 1)3]

= 6[8 + 11 × 3]

= 6[8 + 33]

= 6 × 41

= 246

S12 = 246