Answer :
So lets see first the one for $14000
10000 free and 4000 at 10%
tax = (14000 - 10000) x 0.1
And now for $26000
there is $6000 more that $20 000
$10000 free + $10000 at 10% + 6000 at 15%
so the tax = (20000 - 10000) x 0.1 +6000 x 0.15
10000 free and 4000 at 10%
tax = (14000 - 10000) x 0.1
And now for $26000
there is $6000 more that $20 000
$10000 free + $10000 at 10% + 6000 at 15%
so the tax = (20000 - 10000) x 0.1 +6000 x 0.15