(UDESC) Seja X um conjunto com 6 elementos distintos e seja P(X) o conjunto das partes de X. O número de elementos de P(X) é:

(ENEM 2014 3º APLICAÇÃO)

Uma pessoa precisa comprar creme dental. Ao entrar em um supermercado, encontra uma marca em promoção, conforme o quadro seguinte:

Pensando em economizar seu dinheiro, resolve levar a embalagem de número

(FUVEST 2007 1ª FASE)  

“Researchers and public-health officials have long understood that to maintain a given weight, energy in (calories consumed) must equal energy out (calories expended). But then they learned that genes were important, too, and that for some people this formula was tilted in a direction that led to weight gain. Since the discovery of the first obesity gene in 1994, scientists have found about 50 genes involved in obesity. Some of them determine how individuals lay down fat and metabolize energy stores.

Others regulate how much people want to eat in the first place, how they know when they’ve had enough and how likely they are to use up calories through activities ranging from fidgeting to running marathons. People who can get fat on very little fuel may be genetically programmed to survive in harsher environments. When the human species got its start, it was an advantage to be efficient. Today, when food is plentiful, it is a hazard.”

http://www.nytimes.com/2006/08/13/magazine/13obesity.html.

In the text, the pronoun “Others” (line 14) refers to

(UFJF) Um suco de laranja contém 400 ppm de vitamina C. Quantos mL de suco de laranja uma pessoa deve ingerir para suprir a necessidade diária de 60 mg de vitamina C?

Considere que a densidade do suco de laranja seja 1,00 g/mL.

Dois meios transparentes, A e B, de índices de refração absolutos n_A e n_B­ ≠ n_A são separados por uma superfície plana S e três raios monocromáticos, R₁, R₂ e R₃ se propagam do meio A para o meio B conforme a figura.

É correto afirmar que