We can start by saying that 4/3w+ 3/3w = 133.
we can simplify to 7/3w = 133.
multiply both sides by 3 to get 7w = 399.
divide both sides by 7 to get 57.
Mr. Wong's mass is 57 kg.
20*65 = 1300
That's the price without tax.
Now to find tax:
1300*.035 = 45.5
1300+45.5 = $1345.5
$1345.5 is your total