Gabriela bought a new pair of glasses at the store when they were having a 30%30\% 30% 30, percent off sale. if the regular price of the pair of glasses was $72\$72 $72 dollar sign, 72 , how much did gabriela pay with the discount?

For this case you can solve the problem by a simple rule of three:
 72 ---> 100%
 x ---> 30%
 Clearing x we have:
 x = (30/100) * (72) = 21.6 $
 Then, we must subtract this value from the original price:
 72-21.6 = 50.4 $
 
 Gabriela pays $ 50.4 with the discount

The answer would be: b

Best answer that i found on yahoo ok   set :   x= length of 2nd piece in cm  x- 3= length of 1st piece in cm  x-4= length of 3rd piece in cm  then since you know they all came from the 20 cm ribbon you add them together and set them equal to 20x+ x-3 +x-4 = 20  3x - 7= 20  3x= 27  x= 9  the shortest piece is the third piece which is x- 4  x-4  9-4 = 5  the length of the smallest piece is 5 cm.  the other lengths are  9 cm  6 cm