In an Eight-Cylinder Engine, the Even-Numbered Cylinders Are on the Left

Short Answer

In an eight-cylinder engine, the even-numbered cylinders are on the left and the odd-numbered cylinders are on the right. A good firing order is a sequence of the numbers 1 through 8 in which right and left sides alternate.

a. How many possible good firing sequences are there ?
__________ sequences

b. How many good firing sequences are there that start with a cylinder on the left ?
__________ sequences