If Mario was 32 years old 8 years ago, how old was he x years ago?

The formula gives the relationship between the temperature in degrees Fahrenheit, F, and the temperature given in degrees Celsius, C. If the temperature is 85 degrees Fahrenheit, what is the temperature, to the nearest degree, in degrees Celsius?

Aside from yielding cotton fiber, the cotton plant produces oil-rich seeds from which oil for human consumption is extracted. The seeds contain a natural poison, that must be carefully removed before the oil is extracted. The expense of removing the poison makes cottonseed oil relatively expensive. If biotechnological researchers succeed in engineering cotton whose seeds lack the poison, cottonseed oil could be made more cheaply and sales, therefore, would greatly expand.

Which of the following, if true, most seriously weakens the argument?

Professor: One expert on Norse culture argues that since yarn (fiber thread) samples discovered at non-Norse archaeological sites, those related to the aboriginal Dorset people in the East Arctic, are similar to prehistoric Norse yarn samples, and since spinning was not a part of the technology of northern aboriginal peoples, the Dorset samples constitute proof of contact between these aboriginal people and Norse Vikings. The fact that radiocarbon dating seems to indicate that the Dorset samples predate Norse arrival in the region by centuries is dismissed by the expert as an anomaly attributable to significant problems with the dating of textiles found at Arctic sites. But this position seems questionable, given that _________

Which of the following would, if true, most logically complete the professor's argument above?

Psychology researchers found that manual laborers who were tutored on the fitness value of their tasks experienced marked health improvements. Despite workload and level of recreational exercise remaining constant, within four weeks of learning that their daily tasks provided good exercise, the participants lost an average of two pounds and achieved statistically meaningful reductions in body-fat percentage compared with an untutored group. The psychologists hypothesized that this improvement in fitness levels was a direct result of their heightened perception of themselves as fit.

Which of the following would be most useful to determine in evaluating the hypothesis?

The range of the monthly numbers of customers at a certain store was 240 for the year 1999 and 320 for the year 2000. Which of the following is the smallest possible range of the monthly numbers of customers at the store for the two-year period 1999–2000?

What is the units digit of x² - y² ?

(1) x - y is a positive multiple of 3

(2) x + y is a positive multiple of 10

If f(x,y)= , where 0<x<y, which of the following could be the value of f(x,y) ?

If which of the following must be true?

T is the set of all numbers that can be written as the following sum involving distinct non-zero integers a, b, c and d: . What is the range of T?