Makoto, Nishi, and Ozuro were paid a total of $780 for waxing the floors…
We are given that Makoto, Nishi, and Ozuro were paid a total of $780 for waxing the floors at their school. Each was paid in proportion to the number of hours he or she worked. Since Makoto worked 15 hours, Nishi worked 20 hours, and Ozuro worked 30 hours, we can create the following proportion:
Makoto payment : Nishi payment : Ozuro payment = 15x : 20x : 30x
We can create the following equation to determine x:
15x + 20x + 30x = 780
65x = 780
x = 12
Since x = 12, Makoto was paid 15 x 12 = 180 dollars.
Since we know that Makoto’s payment was equivalent to 15x, we know that his payment must be a multiple of 15. Since 180 is the only multiple of 15, the correct answer must be 180.