V = d / t = 1800 mi / 40 min = 180 mi / 40 min = 45 mi / min .
Which very well could be "Answer choice: [C]: 45 m/min" ; except, this answer choice may have been written incorrectly—and should read: "45 m/min." ________________________________________________________
Now, notice that all the answer choices given are in "meters" per (unit time—seconds or mins.
So, we need to convert:
45 mi. to "meters", or "m". ______________________________________ Note the following conversions: _______________________________________ 1 mi. = 1750 yd ______________________________________ 3 ft. = 1 yd. ____________________________________
1 m = 3.2 ft. _____________________
So, 1 mi. = ? m ; _____________________ 1 mi * ( 1760 yd/ mi) * (3 ft / 1 yd) * ( 1m / 3.2 ft) = _?_ m ? _____________________________________________________ On the "left hand side" , the units of "mi", "yd", and "ft" ; cancel to "1" ; ____________________________________________________ and we are left with: ______________________________________ [(1760 * 3)] / [(3)*(3.2)] m = (5280 / 9.6) m = 550 m . ______________________________________________ So, we have: 550 m / min ; which match NONE of the answer choices.
However, it is possible that choices A or B, which are given in "m/sec" (meters per second); are among the correct choices. ____________________________________________
So, we convert: 550 m / min to: "m / sec " ; ______________________________________ ( 550 m/ min)*(1 min/ 60 sec) = (550/60) m/sec = (55/6) m/ sec = 9 1/6 m / sec . _____________________________________________________ which is: None of the above. ______________________________________________________ Unless the answer choices were written incorrectly.
