Label the missing side and angle measurements

Determine whether the following statements are true and give an explanation or counterexample. bold a. when using the shell method, the axis of the cylindrical shells is parallel to the axis of revolution. bold b. if a region is revolved about the y-axis, then the shell method must be used. bold c. if a region is revolved about the x-axis, then in principle it is possible to use the disk/washer method and integrate with respect to x or the shell method and integrate with respect to y.

Anyone know? will mark brainliest if correct!

Jenisey has $24 to spend on seven pencils. after buying them she had $10. how much did each pencil cost.?