The sum of all two digit numbers divisible by 9 is
Choose the correct answer.
A) 910 B) 585 C) 785 D) 685 E) 885
Required numbers are 18,27 . . . . . 99   This is an A.P. in which a=18,d=9 and l=99.   Let the number of terms in it be n.Then t=99   So a+(n-1)d=99.   18+(n-1)*9=99,   18+9n-9=99   9+9n=99   9n=99-9= 
<gadget id="calculator">99-9</gadget>
<output>90</output>
90/9= 
<gadget id="calculator">90/9</gadget>
<output>10</output>
10.   Required sum=n/2(a+l)   =10/2(18+99)   =585   Answer is 585.
<result>B</result>
The sum of all two digit numbers divisible by 9 is