Question

For an A.P., t1 = 25 and t20 = 405. Find the common difference.​

Answer 1

t20 or a20= a+ (n-1)d

a20 = a+ 19d..

405-19d= a... 1

t1or a1= a+ (n-1)d

a1= a

25= a.... 2

equating 1 and 2,

405- 19d= 25

380= 19d

d= 20

Answer 2

Answer:

d is 20 my bro

Step-by-step explanation:

how??

d

see the above answer