Question

The total number of integers between $200$ and $400$ each of which either begins with $3$ or ends with $3$ or both is ?

• A. $110$
• B. $120$
• C. $200$
• D. $115$

Answer 1

The correct option is A $110$

(i) The ones ending with 3 : 203, 213, 223, ............., 393 ==> 20 numbers.
(ii) The ones beginning in 3 : 300, 301, 302, 303, ...., 393,...., 399 ==> 100 numbers
But 10 out of the first 20 numbers are repeated in the second set.
Therefore, the solution is 110 numbers.