Al fotocopiar una credencial, primero se amplia al triple y posteriormente la copia resultante se reduce a la mitad. ¿cual es el efecto final respecto a la credencial original? si al credencias es un rectángulo de 10 por 6 cm. ¿que área tendrá en la primera fotocopia? ¿y en la segunda?

Using google translate: 
When photocopying a credential, it is first enlarged to triple and subsequently the resulting copy is halved. What is the final effect on the original credential? If the credentials is a rectangle of 10 by 6 cm. What area will you have in the first photocopy? And in the second?

Original: 10 by 6 cm  ;  Area = length * width = 10 x 6 = 60 cm²

first copy: enlarged to triple
10 x 3 = 30 
6 x 3 = 18
30 x 18 = 540 cm²

second copy: halved
30 x 1/2 = 15
18 x 1/2 = 9
15 x 9 = 135 cm²