A
child was asked to add first few natural numbers (i.e. 1+2+3+...) so long his
patience permitted. As he stopped, he gave the sum as 575. When the teacher
declared the result wrong, the child discovered he had missed one number in the
sequence during addition. The number he missed was

a.
less than 10

b.
10

c.
15

d.
more than 15

If the child adds all the numbers
from 1 to 34, the sum of the numbers would be 1+2+3+...+34