Consider the set  of natural numbers and an operation  which means select the first of the two.  That is, ;

class="wirisformula" data-wiris-created="true" src="https://sciemce.com/media/3/ppg__cognero__5.1_Natural_Numbers__media__285c9aaa-3ca6-4e94-8947-914dc375a110.PNG" style="vertical-align:middle;" />; ; .
?
Is  associative for ?
?

A. no
B. yes

---

Answer: B

Mathematics

Solve the problem.What is the ratio of the surface areas for a pair of spheres when the ratio of the radii is 3:2?

A. 3 : 2 B. 9 : 4 C. 27 : 8 D. Not enough information given

The super skyscraper Taipei 101 currently holds the record for tallest building. It’s height is listed as 449 meters. Convert this to feet.

What will be an ideal response?

A landscape designer is working on the plans for a residential yard. Her clients want a privacy hedge planted on three sides of the rectangular backyard. (The side bordering the house will not be planted.) The plant selected for the hedge spans 5 when mature. If the backyard is 50 feet deep and 80 feet long and there is to be a plant at the corners of the hedge, how many hedge plants are required? (See sketch.)

Use Pascal's triangle to expand the binomial.(x + 2)5

A. x5 + 10x4 + 40x3 + 80x2 + 80x + 2 B. x5 + 10x4 + 40x3 + 80x2 + 80x + 32 C. x5 + 10x4 + 80x3 + 160x2 + 80x + 32 D. x5 + 10x4 + 80x3 + 160x2 + 80x + 2