Calculate the sum of first 19 natural numbers.	Choose the correct choice.
A) 190  B) 120  C) 150  D) 199  E) 110
Solution   We know that(1+2+3+.....+19)	= n(n+1)/2   Therefore (1+2+3+....+19)	=(19×20 / 2)   = 190.   190nswer 190
<result>A</result>
Calculate the sum of first 19 natural numbers.