Suppose

is the number of possible combinations for a suitcase with a lock consisting of

wheels. If you added one more wheel onto the lock, there would only be 9 allowed possible digits you can use for the new wheel. This means the number of possible combinations for

wheels, or

is given recursively by the formula

starting with

(because you can start the combination with any one of the ten available digits 0 through 9).
For example, if the combination for a 3-wheel lock is 282, then a 4-wheel lock can be any one of 2820, 2821, 2823, ..., 2829 (nine possibilities depending on the second-to-last digit).
By substitution, you have

This means a lock with 55 wheels will have

possible combinations (a number with 53 digits).
Answer:
The length= 16cm
The width= 6cm
The two long sides are 8cm both so 8 + 8 = 16
And the two short sides are 3cm both so 3 + 3 = 6
So your length should be 16cm and your width 6cm
I HOPE THIS HELPS! ∧ ∧
⊂∵→ω←∵⊃
4n + 8 = n - 7
(In which 'n' represents the unknown number)
(4n + 8): "Eight more than the product of four and a number"
(= n - 7): "Is equivalent to seven less than the same number in equation form."
Subtract 8 from both sides:
4n = n - 15
Subtract n from both sides:
3n = -15
Divide both sides by 3:
n = -5