When is the sum of two negative mixed numbers an integer

Iknow its nothing to do with education, but what type of thing should i wrote here? ? : ) its for mcdonald's btw.

Point r divides in the ratio 1 : 5. if the coordinates of e and f are (4, 8) and (11, 4), respectively, what are the coordinates of r to two decimal places?

Can someone me find the original price? the discount is 5% and the sale price is $68.40