freecodecamp--freecodecamp/curriculum/challenges/english/blocks/daily-coding-challenges-python/68c1a929005bf54d342aa8d4.md

id, title, challengeType, dashedName

id	title	challengeType	dashedName
68c1a929005bf54d342aa8d4	Challenge 57: Space Week Day 3: Phone Home	29	challenge-57

--description--

For day three of Space Week, you are given an array of numbers representing distances (in kilometers) between yourself, satellites, and your home planet in a communication route. Determine how long it will take a message sent through the route to reach its destination planet using the following constraints:

• The first value in the array is the distance from your location to the first satellite.
• Each subsequent value, except for the last, is the distance to the next satellite.
• The last value in the array is the distance from the previous satellite to your home planet.
• The message travels at 300,000 km/s.
• Each satellite the message passes through adds a 0.5 second transmission delay.
• Return a number rounded to 4 decimal places, with trailing zeros removed.

--hints--

send_message([300000, 300000]) should return 2.5.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([300000, 300000]), 2.5)`)
}})

send_message([384400, 384400]) should return 3.0627.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([384400, 384400]), 3.0627)`)
}})

send_message([54600000, 54600000]) should return 364.5.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([54600000, 54600000]), 364.5)`)
}})

send_message([1000000, 500000000, 1000000]) should return 1674.3333.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([1000000, 500000000, 1000000]), 1674.3333)`)
}})

send_message([10000, 21339, 50000, 31243, 10000]) should return 2.4086.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([10000, 21339, 50000, 31243, 10000]), 2.4086)`)
}})

send_message([802101, 725994, 112808, 3625770, 481239]) should return 21.1597.

({test: () => { runPython(`
from unittest import TestCase
TestCase().assertEqual(send_message([802101, 725994, 112808, 3625770, 481239]), 21.1597)`)
}})

--seed--

--seed-contents--

def send_message(route):

    return route

--solutions--

def send_message(route):
    total_distance = sum(route)
    delay = (len(route) - 1) * 0.5
    time = total_distance / 300_000
    total = time + delay
    return round(total, 4)