Question

the 1st term of an A.P is 2 and the 20th term is 59, find the common difference of the A.P

Answer 1

let a be the first term
and d be the common difference then,
nth term=a+(n-1)d
1th term=a+(1-1)d
2=a+0
a=2
20th term=a+(20-1)d
2+19d=59
19d=59-2
19d=57
d=57/19
d=3

Answer 2

so given first term(a)= 2
given 20 th term = 59
so using formula
value nth term = a + (n - 1)d      where n = no. of terms
59 = 2 + (20 - 1)d
d = 57/19 
d = 3
so common difference = 3