What is to do when you have to use more than one unknown?

If i have one apple and give you the apple, how many apples do i have?

Marion has a bicycle that she is planning to take for a ride. the rim of the rear wheel lies 41 cm from the center of the wheel. the tire itself has a thickness of 3 cm. in order for marion to ride her bicycle 96,712 cm approximately how many rotations will the rear wheel make?

Apolice office claims that the proportion of people wearing seat belts is less than 65%. to test this claim, a random sample of 200 drivers is taken and its determined that 126 people are wearing seat belts. the following is the setup for this hypothesis test: h0: p=0.65 ha: p< 0.65 find the p-value for this hypothesis test for a proportion and round your answer to 3 decimal places.