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

Required numbers are 10, 15, 20, 25, ..., 95

This is an A.P. in which a = 10, d = 5 and l = 95.

t_n = 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