Hi you can use the #each_wi= th_index method to iterate through the array and also get the position numb= er of each element=2C then call #map to build an array with the result of e= ach iteration and finally the #inject method combines all the elements in t= he array with the + method.

def lassy_sum(numbers)= # if numbers is [1=2C2=2C3]

=3B result =3D numbers.each_wit= h_index.map { |n=2C i| n*i } # this will return [0=2C2=2C6]

= =3B result.inject(:+) # this will return 8

end

By the way=2C the # character in Ruby after each line means that everythi= ng after it is a comment and doesn't affect the execution of the code.

= You can try this code on irb=2C just do the following:

1. Open your terminal =3B

2. Type: =3Birb

3. Press Enter

4. Paste the code that i have proposed

= 5. Type: lassy_sum [1=2C2=2C3]

6. It should return: 8

Javie= r Hidalgo V.
L=EDder de Desarrollo=

>=3B Date: Thu=2C 16 May 2013 06:46:51 +0900=
>=3B From: lists@ruby-forum.com
>=3B Subject: n00b looking to le= arn from the best
>=3B To: ruby-talk@ruby-lang.org
>=3B
>= =3B Hey Rubyians!
>=3B
>=3B I am not used to joining online foru= m's and I am eager to join the Ruby
>=3B community. This is the first = language I am learning and have a practice
>=3B problem that I cannot = seem to get. Can you enlighten me? I'm looking
>=3B forward to learnin= g from all of you!
>=3B
>=3B Here is the question:
>=3B >=3B Write a method named lassy_sum(numbers) that takes an array of numb= ers.
>=3B lassy_sum should multiply each number in the array by its po= sition in
>=3B the array=2C and return the sum.
>=3B
>=3B I= don't quite understand how to multiply each number in the array by its
= >=3B position in the array. Any help will be greatly appreciated! Thanks.=
>=3B
>=3B Flex
>=3B
>=3B --
>=3B Posted via ht= tp://www.ruby-forum.com/.
>=3B

Javie= r Hidalgo V.L=EDder de Desarrollo=

Javie= r Hidalgo V.
L=EDder de Desarrollo=