Simplify 15r+6(60-r) what are the units associated with the entire expression

So far, there is no units we can see becaus we have no context what this is trying to find

so
use the distributive property which goes like this: a(b+c)=ab+ac
so
first distribute

6(60-r)=6(60)+6(-r)=360-6r

now we have
15r+360-6r=
15r-6r+360=
9r+360
there are no units associated with the expression

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.