The method of double$-$declining balance depreciation is a form of depreciation that uses a multiple of $200\%$ of the straight$-$line rate. The amount of annual depreciation decreases as time goes on and is calculated using the declining$-$balance rate given below.

declining $-$ balance rate $=$

$1$

useful life $($years$)$

$$ straight$-$line multiple

The declining$-$balance rate and total cost of the truck when it was new must be calculated before the depreciation schedule can be created. The trucks should last $7$ years, so the useful life of these trucks is $7$ years. The method of double$-$declining balance depreciation will be used, so the straight$-$line multiple is $200\%.$ Calculate the declining$-$balance rate $($as a $\%),$ rounding the result to six decimal places.

declining $-$ balance rate $=$

$1$

useful life $($years$)$

$$ straight$-$line multiple