Which statement is true about the value of (6^-n)(6^n)

Write the sentence as an equation. 6 fewer than the quantity 140 times j equals 104

The wheels of a bicycle have a diameter of 70cm. how many meters will the bicycle travel if each wheel makes 50 revolutions

Bob the builder is making 480kg of cement mix. this is made by cement, sand and gravel in the ratio 1: 3: 4