Question

sum of 3terms is30 and 13terms sum is 520. what is 3rd term and common difference​

Answer 1

Answer:

Step-by-step explanation:

sum of three terms is 30

a-d + a + a+d = 30

3a = 30 and a = 10

using  Sn=n/2(2a+(n-1)d)

520 = 13/2 ( 20 + 12d)

520*2/13 = 20 + 12d

80-20 = 12d , 60/12 = d and d = 5

first term = 10 and common difference = 5

Answer 2

Answer:

may be like This it can be solved