Below is an instruction that describes a task. Write a response that appropriately completes the request in French. Please answer in French.

### Instruction:
 John weighs one-quarter times more than what Mary weighs. Mary weighs 20 lbs less than Jamison's weight. If Mary weighs 160 lbs, what's the combined weight of the three?


### Response:
 Si Mary pèse 160 livres, Jamison pèse 160 livres + 20 livres = <<160+20=180>>180 livres.
John pèse un quart de moins que ce que Mary pèse, soit un total de 1/4 * 160 livres = <<1/4*160=40>>40 livres
Le poids total pour John est de 40 livres + 160 livres = <<40+160=200>>200 livres.
Pour les trois, le poids total est de 200 livres + 180 livres + 160 livres = <<200+180+160=540>>540 livres.