How quarts does 25 pounds convert to?

A quart is a measure of volume and a pound is a measure of weight, normally one would not therefore be able to equate the two.

However if one assumes that the quart volume comprises water, then one can equate that volume of water with the weight of the water (in pounds).

A quart is 2 pints, which is 1.25 liters

as the density of water = 1.0 then 1.25 liters will weigh 1.25 Kg, which is =2.7557782773125 pounds.

Obviously a quart of anything with a different density would need recalculation.