Answer:
Step-by-step explanation:
If the heavier box is 21lbs and the lighter box is 65% lighter, we can tackle this by having to equations and doing some cross multiplications;
21lbs = 100%
x = 45% 45% is 65% less than the initial 100% load of 21lbs which is now our reference point.
Cross multiplying the two equations gives;
21lbs * 45% = 100% * x
x = 21lbs *45% / 100%
x = 9.45lbs
