Question

A pinewood can be at most 2 3/4 inches wide. About how many Pinewood derby cars can be displayed side by side on a shelf that is 31 1/2 inches long

Answer 1

11 cars can be placed side by side.

Explanation:

Given:

Width of the pinewood derby can is,
`w=2(3)/(4)\ in`

Total width available to place the cars side by side =
`W=31(1)/(2)\ in`

Converting the mixed fraction to decimal form:

`w=2(3)/(4)=2+(3)/(4)=2+0.75=2.75\ in\\W=31(1)/(2)=31+(1)/(2)=31+0.5=31.5\ in`

Now, the total width available will be used by the cars without any space between them.

The formula to determine the number of pinewood derby cars is given as:

`\textrm{Number of cars}=\frac{\textrm{Total width}}{\textrm{Width of 1 car}}\\\\ \textrm{Number of cars}=\frac{\textrm{W}}{\textrm{w}}`

Plug in the given values and determine the number of cars that can be displayed side by side. This gives,

`\textrm{Number of cars}=(31.5)/(2.75)\\\\\textrm{Number of cars}=11.45\approx11`

Therefore, 11 cars can be placed side by side.