Question

A box of 12" drafting scales weighs 3 3/4 lbs. A dealer has 20 1/2 boxes in stock. What is the total weight of the scales?

Answer 1

`76(7)/(8)\ lb`

Explanation:

we know that

One box of 12'' weighs 3 3/4 lb

so

To find out the weight of 20 1/2 boxes, multiply the weight of one box by the total number of boxes

`3(3)/(4)(20(1)/(2))`

Convert mixed number to an improper fraction

`3(3)/(4)\ lb=(3*4+3)/(4)=(15)/(4)\ lb`

`20(1)/(2)\ boxes=(20*2+1)/(2)=(41)/(2)\ boxes`

substitute

`(15)/(4)((41)/(2))=(615)/(8)\ lb`

Convert to mixed number

`(615)/(8)\ lb=(608)/(8)+(7)/(8)=76(7)/(8)\ lb`