here are 2 math promblems please help

3. The original price of the trampoline is $72
The marked off price is 72 times 70 percent.
72 x .70 = 50.4
The sales tax is 5%
50.4 + 50.4 x 0.05
50.4 + 2.52
52.92
He paid $52.92 in total.
4. A store bought a leaf blower for $48.50 and marked it up 100%
This cost would be 48.5 x 2 which is $97
The sales tax is 6%
97 + 97 x 0.06
97 + 5.82
102.82
The total cost was $102.82