Question

Difficult question that my online tutor cannot even answer

Answer 1

The Gladstone harbour board decides to issue private boats using the Gladstone harbour with 7 digit registration numbers. None of these can start with zero. The harbour board had only been able to get the digits 0, 1, 2, 3, 4, 5, 7, 9 for the boat registration numbers. No digit may be used more than once in each registration number.
Bruno, who was responsible for allocating the registration numbers to the boats, had the bright idea of using the number 9 upside down to make 6. However, the 6 and 9 cannot both occur in the same registration number.
The registration numbers are issued in ascending orider. Thus the first registration number is 1023567. The next two are 1023576 and 1023579.
What is the registration number on the 7000th boat?

Answer 2

@ozhobbits Well, before we start let me ask you have you solved this kind of problems in class before?

Answer 3

@ozhobbits

Answer 4

no

Answer 5

i am in year 10 :(

Answer 6

let's try to solve it together

Answer 7

we have to find the combination of 7 digit numbers, right?

Answer 8

and as you can see we can not have 9 or 6 in the same registration number, right?

Answer 9

yes

Answer 10

okay
so, the first number would be

Answer 11

this is given by the problem
so far is that clear?

Answer 12

yes

Answer 13

the first number is one for sure.

Answer 14

and what we can say is that how many combinations we would have for the first column?

Answer 15

as you can see we can use: 1 , 2 ,3 , 4 , 5 , 7 9 and the 9 as a 6
right?