Q-2: How many two digit numbers of distinct digits can be formed by using digits 1, 2, 3, 4, 5, 6 and 7 such that the numbers are divisible by 3?  Choose the correct choice from the following.
A) 9 B) 10 C) 11 D) 12 E) 14
CONCEPT: A number will be divisible by 3 if sum of all the digits of the number is divisible by 3   Here the Possible sum of the two distinct digits can be 3, 6, 9 and 12 only in order to satisfy the given condition   If sum of Digits = 3, No. = 12, 21 --- 2 Cases   If sum of Digits = 6, No. = 15, 24, 42, 51 --- 4 Cases   If sum of Digits = 9, No. = 27, 36, 45, 54, 63, 72 --- 6 Cases   If sum of Digits = 12, No. = 57, 75 --- 2 Cases   Total Cases = 2+4+6+2= 
<gadget id="calculator">2+4+6+2</gadget>
<output>14</output>
14 cases   Answer: option 14
<result>E</result>
Q-2: How many two digit numbers of distinct digits can be formed by using digits 1, 2, 3, 4, 5, 6 and 7 such that the numbers are divisible by 3?