Abe chooses a number from Group A, Bob chooses a number from Group B and Charlie chooses a number from Group C.
Group A: 741 345 624 813
Group B: 519 825 717 456
Group C: 134 260 503 152
Then Abe chooses a digit X from his number, Bob chooses a digit Y from his number and Charlie chooses a digit Z from his number. The digits are arranged to form the three-digit number XYZ. Abe, Bob and Charlie, in that order, then choose different digits from their selected numbers to form a second three-digit number. Finally, in the same order, they use the remaining digits to form a third three-digit number. What is the sum of the three numbers that are formed?
A sequence begins 1, 2, …, and each term after the second term is the sum of all preceding terms. What is the 15th term of this sequence?
A certain computer program will take 2000 years to run using current technology. Every year, advances in technology make it possible to run the program in half the time it would have taken starting in the previous year. However, once the program is started it cannot be interrupted to apply newer technology. Including the years spent waiting to start, what is the least number of years it will take to finish running the program? Express your answer to the nearest whole number.
A 3-4-5 right triangle made of paper is cut along the altitude from the right angle, resulting in 2 smaller right triangles. These 2 triangles are then cut along the altitudes from their right angles, then the 4 resulting right triangles are cut the same way and finally, 8 triangles are cut the same way, resulting in 16 smaller right triangles. What is the sum of the perimeters of these 16 triangles? Express your answer as a decimal to the nearest tenth.
If 2015 + a = b for positive integers a and b, both of which are palindromes, what is the smallest possible value of a?