Problem 77

Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle three cards?

(A) 8 (B) 9 (C) 10 (D) 11 (E) 12

ANSWER:D

Problem 76

Pat is to select six cookies from a tray containing only chocolate chip, oatmeal, and peanut butter cookies. There are at least six of each of these three kinds of cookies on the tray. How many different assortments of six cookies can be selected?

(A) 22 (B) 25 (C) 27 (D) 28 (E) 729

ANSWER:B

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Problem 75

A base-10 three digit number n is selected at random. Which of the following is closest to the probability that the base-9 representation and the base-11 representation of n are both three-digit numerals?

(A) 0.3 (B) 0.4 (C) 0.5 (D) 0.6 (E) 0.7

ANSWER: B

Problem 73

Let n be the largest integer that is the product of exactly 3 distinct prime number d,e, and 10d+e, where d and e are single digits. What is the sum of the digits of n?

(A) 12 (B) 15 (C) 18 (D) 21 (E) 24

ANSWER: A

Problem 67

It takes Mary 30 minutes to walk uphill 1 km from her home to school, but it takes her only 10 minutes to walk from school to her home along the same route. What is her average speed, in km/hr, for the round trip?

(A) 3 (B) 3.125 (C) 3.5 (D) 4 (E) 4.5

ANSWER: A