Miguel did 1 push-up on Sunday, 3 push-ups on Monday, 9 push-ups on Tuesday, and 27 push-ups on Wednesday. What kind of sequence is this?

1 answer

The sequence of push-ups Miguel did can be described as a geometric progression.

To analyze the sequence:

  • On Sunday, he did 1 push-up.
  • On Monday, he did 3 push-ups.
  • On Tuesday, he did 9 push-ups.
  • On Wednesday, he did 27 push-ups.

To determine the pattern, we can observe the relationship between consecutive terms:

  • From Sunday to Monday: \( 3 = 1 \times 3 \)
  • From Monday to Tuesday: \( 9 = 3 \times 3 \)
  • From Tuesday to Wednesday: \( 27 = 9 \times 3 \)

Here, each term is obtained by multiplying the previous term by 3.

The general formula for the \( n \)-th term of a geometric sequence can be expressed as: \[ a_n = a_1 \cdot r^{(n-1)} \] where \( a_1 \) is the first term, \( r \) is the common ratio, and \( n \) is the term number.

In this case:

  • The first term \( a_1 = 1 \),
  • The common ratio \( r = 3 \).

Thus, the sequence can be represented as:

  • \( a_1 = 1 \)
  • \( a_2 = 1 \cdot 3 = 3 \)
  • \( a_3 = 1 \cdot 3^2 = 9 \)
  • \( a_4 = 1 \cdot 3^3 = 27 \)

Therefore, this is a geometric sequence with a common ratio of 3.