# Question #a0237

##### 1 Answer

#### Explanation:

All you have to do here is use two **conversion factors**, one that takes you from *inches* to *feet* and the other that takes you from *months* to *days*.

The first conversion factor is

#color(purple)(|bar(ul(color(white)(a/a)color(black)("1 ft " = " 12 in")color(white)(a/a)|)))#

Now, let's work on the second conversion factor a bit. As you know, a *common year* has **days**. Once every four year, we get a *leap year*, which has **days**.

This means that every * common years* and

*. The average number of days in a year will be*

**leap year**

#"no. of days / year" = (3 xx "365 days" + "366 days")/4 = "365.25 days"#

Now, a year has **months**, which means that **month** will have an average of

#1 color(darkgreen)(cancel(color(black)("month"))) * (1color(red)(cancel(color(black)("year"))))/(12color(darkgreen)(cancel(color(black)("months")))) * "365 days"/(1color(red)(cancel(color(black)("year"))))= "30.4375 days"#

Your second conversion factor will thus be

#color(purple)(|bar(ul(color(white)(a/a)color(black)("1 month " = " 30.4375 days")color(white)(a/a)|)))#

Use these two conversion factors to find

#0.5color(white)(a) color(blue)(cancel(color(black)("in")))/color(red)(cancel(color(black)("month"))) * "1 foot"/(12color(blue)(cancel(color(black)("in")))) * (1color(red)(cancel(color(black)("month"))))/"30.4375 days" = "0.001369 ft/day"#

Now, you only have one **sig fig** for the initial measurement, which can only mean that the answer **must** be rounded off to one sig fig. You thus have

#color(green)(|bar(ul(color(white)(a/a)color(black)("0.5 in/month " = " 0.001 ft/day")color(white)(a/a)|)))#