Question

for an AP t1=25 &t20=405. find the common difference​

Answer 1

Answer:

common difference is 20

Step-by-step explanation:

t1 = 25

It means a = 25

t20 = 405

a + 19d = 405

But we already know a = 25

25 + 19d = 405

19d = 405 - 25

19d = 380

d = 380/19

d = 20