find the 21 th term of an arithmetic progression whose first term is 3 and the common difference is 5 .
"n th term of a . p = a + ( n - 1 ) * d = 3 + ( 21 - 1 ) * 5 , = 3 + 100 = 103 . answer : c"
add(multiply(subtract(21, const_1), 5), 3)