I need help on #3 , can anyone help me?

1mile equals approximately 1.6 kilometers. which best approximates the number of miles in 6 kilometers?

Four individuals pool money together to start a new business and agree to split the profits equally. n invests $6,000, x invests $2,000, y invests $8,000 and z invests $4,000. if the profits for the first month were $100,000, y receives than if the profits were divided in proportion to how much they invested.

Determine which postulate or theorem can be used to prove that lmn =nmo