Kit made contributions to a Roth IRA over the course of 30 working years. His contributions averaged $4,000 annually. Kit was in the 24% tax bracket during his working years. The average annual rate of return on the account was 6%. Upon retirement, Kit stopped working and making Roth IRA contributions. Instead, he started living on withdrawals from the retirement account. At this point, Kit dropped into the 15% tax bracket. Factoring in taxes, what is the effective value of Kit's Roth IRA at retirement? Assume annual compounding. (3 points) a $287,432.74
b $305,432.74
c $240,336.88
d $298,232.74

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)