James can do a farmer's walk with 300 pounds per hand for 20 meters.  He can lift 30% more if he only goes 10 meters.  In addition, lifting straps give him another 20%.  How much can he move with lifting straps for 10 meters if he increases his 20-meter distance without straps by 50 pounds and everything else increases in proportion?
After the increase, he can lift 300+50=
<gadget id="calculator">300+50</gadget>
<output>350</output>
350 pounds.
Decreasing the distance increase the amount he can lift by 350*.3=
<gadget id="calculator">350*.3</gadget>
<output>105</output>
105 pounds.
So he can lift 350+105=
<gadget id="calculator">350+105</gadget>
<output>455</output>
455 for 10 feet.
The straps add another 455*.2=
<gadget id="calculator">455*.2</gadget>
<output>91</output>
91 pounds.
So his total weight is 455+91=
<gadget id="calculator">455+91</gadget>
<output>546</output>
546 pounds per hand.

<result>546</result>