John can front squat 80% as much as he back squats.  He used to back squat 200 kg but increased that by 50 kg.  He can do a triple equal to 90% of the amount he front squats.  How much weight will he move if he does three triples?
He increased his back squat to 200+50=
<gadget id="calculator">200+50</gadget>
<output>250</output>
250 kg.
That means his front squat is 250*.8=
<gadget id="calculator">250*.8</gadget>
<output>200</output>
200 kg.
So he can do a triple with 200*.9=
<gadget id="calculator">200*.9</gadget>
<output>180</output>
180 kg.
So he moves 180*3 = 
<gadget id="calculator">180*3</gadget>
<output>540</output>
540 kg if he does three triples.

<result>540</result>