Question

how many two digit numbers are divisible by 3

Answer 1

So, the A.P. will be 12, 15, 18, 21, ………….99 We need to find n Last term of this series is 99 So, an = 99 & a = 12d = 15 – 12 = 3 Now, an = a + (n – 1) d Putting values 99 = 12 + (n – 1) (3) 99= 12 + 3n – 3 99 = 9 + 3n 3n = 99 – 9 3n = 90 n = 90/3 = 30 Therefore , there are 30 two digit numbers divisible by 3.

Answer 2

12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 78 81 84 87 90 93 96 99 are two digit nos. which can be divisible by 3.
Total - 30..