How many numbers can be formed by using digits 0 to 9, as the number should be divisible by 5 and it...
How many numbers can be formed by using digits 0 to 9, as the number should be divisible by 5 and it should be 4 digit one and no repitation is allowed on digits?
Answer/Solution
952 ways
Steps/Work
For a number to be divisbly by 5 we have two choices 0 or 5
case 1 : when choice is 0
_ _ _ 0 first digt can be filled in 9ways , 2nd in 8 ways, 3rd in 7 ways so 9 * 8 *7 = 504
case 2 : when choice is 5
_ _ _ 5 first digi can be in 8 ways (since 0 cannot come ) , 2nd in 8 ,3rd in 7 so 8*8*7 = 448
so it can be in 504 + 448 = 952 ways
ANSWER:B
case 1 : when choice is 0
_ _ _ 0 first digt can be filled in 9ways , 2nd in 8 ways, 3rd in 7 ways so 9 * 8 *7 = 504
case 2 : when choice is 5
_ _ _ 5 first digi can be in 8 ways (since 0 cannot come ) , 2nd in 8 ,3rd in 7 so 8*8*7 = 448
so it can be in 504 + 448 = 952 ways
ANSWER:B