Question

If it takes one minute to gift-wrap an area of 1 square meter, find the approximate time required (in hours) to gift-wrap all the sides of the given box.

• A. 2 h
  
• B. 1 h
  
• C. 3 h
  
• D. 4 h
  

Answer 1

The correct option is A 2 h


All six sides of the box have to be wrapped, which means the total surface area of the box will be wrapped.

Length of the box = l = 4.5 m
Width of the box = w = 3.5 m
Height of the box = h = 5.5 m

Total surface area $=2(lw+wh+lh)$
$=2(4.5\times 3.5+3.5\times 5.5+4.5\times 5.5)$
$=2(15.75+19.25+24.75)$
$=2\times 59.75=119.5$ sq m

So, an area of 119.5 sq m needs to be wrapped.

Time taken to wrap an area of 1 sq m = 1 min
So, the time taken to wrap an area of 119.5 sq m $=119.5\times 1=119.5min\approx 120min=2h$