The following sequence is lined in accordance with certain rules.
(1) Find the fourth number from the left of the seventh step.
(2) Find the second number from the right of the twelfth step.
(3) Find the sum total of numbers of the twelfth step.
Answer
(1) 20
(2) 11
(3) 2048
Solution
(1) As shown in the figure below, 4th number from the left of the 7th step is 20.
(2) The 2nd number from the right is to be the number of the step minus one.
Therefore it i s 12 - 1 =11.
(3) The sum total of numbers of each step can be calculated as multiply 2 times of the number of step minus one.
Therefore the sum total of numbers of 12th step is 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 2048.
(1) Find the fourth number from the left of the seventh step.
(2) Find the second number from the right of the twelfth step.
(3) Find the sum total of numbers of the twelfth step.
Answer
(1) 20
(2) 11
(3) 2048
Solution
(1) As shown in the figure below, 4th number from the left of the 7th step is 20.
(2) The 2nd number from the right is to be the number of the step minus one.
Therefore it i s 12 - 1 =11.
(3) The sum total of numbers of each step can be calculated as multiply 2 times of the number of step minus one.
Therefore the sum total of numbers of 12th step is 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 × 2 = 2048.
