How many 7s in 555756756775775565556 are immediately preceded by 6 but NOT immediately followed by 5
- print Print
- list Cite
Expert Answers
calendarEducator since 2012
write1,275 answers
starTop subjects are Math and Science
555756756775775565556
There are a total of six 7's in the given number. But we need to determine the number of 7's that satisfy the condition that the 7 is preceded by 6 but NOT followed by 5.
Starting from the left, let's try to check the number before and after 7.
_ _ 575_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
>The 7 here is preceded by 5 and followed by 5, so this does not satisfy the condition above.
_ _ _ _ _675 _ _ _ _ _ _ _ _ _ _ _ _ _
> The 7 is preceded by 6 and followed by 5. Still, this does not satisfy the given condition.
_ _ _ _ _ _ _ _ 677_ _ _ _ _ _ _ _ _ _
> The 7 is preceded by 6 and followed by 7. Hence this satisfy the condition the number before7should be 6 and after it ,should not be 5.
_ _ _ _ _ _ _ _ _ _ _ _775_ _ _ _ _ _
> The 7 is preceded by 7 and by 5. Again, this does not satisfy the above condition.
Hence, the number of 7's that is preceded by 6 and not followed by 5 is one only.
Related Questions
- How do I solve 6 3/4 + 1 5/6?
- 2 Educator Answers
- Why does 5/6 divided by 1/2 equal 5/6 multiplied by 2/1?
- 1 Educator Answer
- How many 7-digit numbers are there in which every digit is a 6 or a 7 and no two 7s are adjacent?
- 1 Educator Answer
- the one-to-one functions g and h are defined as follows. g={(-4, -5), (1, 2), (7,1), (8, 5)}...
- 1 Educator Answer
- proof by induction that n(n² + 5) can be divided by 6?
- 1 Educator Answer
Unlock This Answer Now
Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.