Numbers - General Aptitude

Q1:

The sum of all two digit numbers divisible by 5 is:

A 1035

B 1245

C 1230

D 945

E None of these

ANS:D - 945

Required numbers are 10, 15, 20, 25, ..., 95 This is an A.P. in which a = 10, d = 5 and l = 95. tn = 95        a + (n - 1)d = 95  10 + (n - 1) x 5 = 95  (n - 1) x 5 = 85  (n - 1) = 17  n = 18

Requuired Sum = n (a + l) = 18 x (10 + 95)   = (9 x 105)   = 945.
2 2