Can you please help me on this?

Question

Will a stand that can hold up to 40 pounds support a 21-kilogram television? Explain. Use 2.2 lb= 1 kg.

Answer 1

The problem gives both the weight limit of the stand (in pounds) and the "conversion factor" needed to convert lb into kg.  Units are very important here.

 

    (40 lbs) / (2.2 lb/kg) = 18.18 kg      { note: we could write [ (40 lb)*(1 kg)/(2.2lb) ]

                The point is that we multiply by 1/1 so that the amount does not change;

                     only the units change, because lb cancels out, leaving only kg  }

 

Will the stand support a 21-kg television?  Actually, the way the problem is worded ("up to"), we don't know for sure.  We know that 40 lb = 18.18 kg and that is more than the "up to" value given in the problem.  If the stand would break with more than 40 pounds, then a 21-kilogram TV breaks it.

Answer 2

Convert 21 kg to pounds using the formula 2.2 lb = 1 kg as follows:

 

TV weight in lbs = (21 kg) * (2.2 lb/kg) = ____ lb

 

If it's more than 40 pounds, then the stand won't support the TV.