Challenge 1
A tank can be filled by one pipe in one hour, by another in two, by a third in three, and by a fourth in four. How long will it take for all four pipes together to fill the tank?
pg.6
Challenge 2
The sum of two numbers is 26, and their product is 153. What are the numbers?
(Consider using google sheets to speed up your problem solving process.)
pg.50
Challenge 3
Place the numbers 1 through 9 in the boxes below so that both multiplications are true.
Challenge 4
If Sally can type one digit in one second, how long will it take her to type out all the numbers from 1 to 2000?
pg. 46
Challenge 5
A and B are integers that between them contain each of the digits from 0 to 9 once and only once. What is the maximum value of A x B?
pg. 116
Challenge 6
Find a ten-digit number whose first digit is the number of ones in the number, whose second digit is the number of twos in the number, whose third digit is the number of threes in the number, and so on up to the tenth digit, which is the number of zeros in the number.
pg. 115
Challenge 7
A sheet of paper 0.01 cm is folded fifty times in succession. How thick is the resulting wad of paper?
pg. 114
Challenge 8
Find three different primes where the average of any two is a prime, and the average of all three is a prime.
Pg. 114
Challenge 9
Let p and q be positive integers. If p is a perfect square and the difference between (p+q) and pq is 1000, find q.