Question 1108473
the first improvement saves you 25% of the cost.


your second improvement saves you an additional 55% of the cost after the first improvement.


your third improvement saves you an additional 20% of the cost after the second improvement.


the costs starts with x.


after the first improvement, the cost is x - .25 * x = .75 * x.


after the second improvement, the cost is .75 * x - .55 * .75 * x = .3375 * x.


after the third improvement, the cost is .3375 * x - .20 * .3375 * x = .27 * x.


you went from x to .27 * x.


this is a reduction in cost of .73 = 73%.


that's your overall savings percent.


to see how this works assume the original cost was 1,000.


take off 25% from that to get a first improvement cost of 750.


take off 55% from that to get a second improvement cost of 337.50.


take off 20% from that to get a third improvement cost of 270.


your cost went from 1,000 to 270.


that's a reduction in cost of 730.


the reduction percent is 730 / 1000 = .75 = 73%.