8th grade

a rabbit can climb one or two steps at a time on a ten step staircase, but he never goes back down. In how many different ways can the rabbit climb a flight of ten steps

  1. 👍
  2. 👎
  3. 👁
  1. 5 2's -- one way
    4 2's 2 1's ---- number of ways = 6!/(4!2!) = 15
    (e.g. 222211, 11222, 212122, etc )

    3 2's 4 1's ---- number of ways = 7!/(4!3!) = 35
    2 2's 6 1's ---- number of ways = 8!/(2!6!) = 28
    1 2 8 1's ---- number of ways = 9!/(1!8!) = 9
    all 1's ---- one way

    total 1+15+35+28+9+1 = 89

    Wow for grade 8!!!

    1. 👍
    2. 👎
  2. 89

    1. 👍
    2. 👎
  3. I'm lost... what does 7i(backwords)(4i3i) means?
    What does the i facing down stands for?

    1. 👍
    2. 👎

Respond to this Question

First Name

Your Response

Similar Questions

  1. physics

    A new record for running the stairs of the Empire State Building was set on February 3, 2003. The 86 flights, with a total of 1576 steps, was run in 9 minutes and 33 seconds. If the height gain of each step was 0.20 m, and the

  2. Physics

    When an 81.0 kg adult uses a spiral staircase to climb to the second floor of his house, his gravitational potential energy increases by 2.25 103 J. By how much does the potential energy of a 17.0 kg child increase when the child

  3. math

    Consider the sequence of steps to solve the equation: 5(x - 3) = 7x 2 Step 1 ⇒ 10(x - 3) = 7x Step 2 ⇒ 10x - 30 = 7x Step 3 ⇒ 3x - 30 = 0 Step 4 ⇒ 3x = 30 Step 5 ⇒ x = 10 Identify the property of equality which yields

  4. math

    a rabbit climb up a flight of 10 stairs and can only hop 1 or 2 steps each time. he never hops down, only up. How many ways can the rabbit hop up the flight of 10 steps?

  1. chemistry

    1)Thallium (I) is oxidized by cerium (IV) as follows: Tl+ + 2 Ce+4  Tl+3 + 2 Ce+3 The elementary steps, in the presence of Mn(II), are as follows: Step 1 Ce+4 + Mn+2 --- Ce+3 + Mn+ Step 2 Ce+4 + Mn+3 ---- Ce+3 + Mn+4 Step 3 Tl+

  2. Help PLZ!!

    consider the steps to simplify the expression. Which property is used to reach Step 3? Expression: -4 3 7 + 7 + (-3 4 7 ) Step 1: = -4 3 7 + (-3 4 7 ) + 7 Step 2: = -4 + (- 3 7 ) + (-3) + (- 4 7 ) + 7 Step 3: = -4 + (- 3 7 ) + (-

  3. physics

    A record was set for stair climbing when a man ran up the 2300 steps of the Empire State Building in 10 minutes and 20 seconds. If the height gain of each step was 0.2 m, and the man's mass was 63.0 kg, what was his average power

  4. math/word problem

    it takes 6 cubes to build a staircase with 3 steps. how many cubes will be needed for 11 steps?

  1. math

    An equation and the steps to solve it are shown below: 3x − one over two (8x − 2) = 4 Step 1: 3x − 4x + 1 = 4 Step 2: x + 1 = 4 Step 3: x + 1 − 1 = 4 − 1 Step 4: x = 3 Which step was the error made and why? Step 1,

  2. math

    Consider the sequence of steps to solve the equation: 2(x − 4) + 6x = 9x − 10 Which step in solving this equation is justified by the Commutative Property of Addition? Given ⇒ 2(x − 4) + 6x = 9x − 10 Step 1 ⇒ 2x − 8

  3. English grammar

    Use a singular verb with sums of money or periods of time. Ex) Ten dollars _____ a high price to pay. Ten dollar is a sum of money, so you have to use a singular verb. In this case, the subject acts as a unit. I'll give you

  4. Algebra

    A brick staircase has a total of 16 steps The bottom step requires 112 bricks. Each successive step requires 4 fewer bricks than the prior one. How many bricks are required to build the staircase?

You can view more similar questions or ask a new question.