Unfortunately, you have not provided all of the necessary info to solve this problem. So I have to make some assumptions. Assume that the 152 lb 4 oz biker can carry a 22 lb backpack. What fraction of 152 lb 4 oz is 22 lb?
Form the ratio 22 lb
---------------- = ?
152 lb 4 oz
Convert 152 lb 4 oz to lb: 152 lb 4 oz = 152.25 lb
Then
Form the ratio 22 lb 22 lb 88
---------------- = --------------- = ------- 152 lb 4 oz 152.25 lb 609
Now, each biker may / can / must carry a backpack weighing (88/609) times his or her own weight.
I weigh 251 lb. Therefore, I must carry a backpack weighing (88/609)(251 lb), or 36.27 lb.