Question 100901
First find out what Martha actually paid for each item.
The $60 skirt was 40% off so to find out how much she paid
multiply 60 times .40
{{{(60)(.40)=24}}}
Marth saved $24 on the skirt
So the actual price paid is 
$60-$24
So the skirt cost $36
Now the $40 blouse was 20% off
multiply 40 times .20
{{{(40)(.20)=8}}}
Martha saved $8 on the blouse
Actual price paid for the blouse is
$40-$8
The blouse cost $32
Ok now we can find what percentage discount she received on the total purchase.
The total price before discount is
$60+$40=$100
The total price with the discount is
$36+$32=$68
Ok so the percentage we are looking for is 
$68 is what percent of $100
It should be easy to see that the answer is 68% but lets do the math.
Divide $68 by $100
{{{68/100}}}
{{{.68}}}
now multiply by 100 to get percent
68%