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

id, title, challengeType, dashedName

id	title	challengeType	dashedName
68c1a929005bf54d342aa8d4	Challenge 57: Space Week Day 3: Phone Home	28	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--

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

assert.equal(sendMessage([300000, 300000]), 2.5);

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

assert.equal(sendMessage([384400, 384400]), 3.0627);

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

assert.equal(sendMessage([54600000, 54600000]), 364.5);

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

assert.equal(sendMessage([1000000, 500000000, 1000000]), 1674.3333);

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

assert.equal(sendMessage([10000, 21339, 50000, 31243, 10000]), 2.4086);

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

assert.equal(sendMessage([802101, 725994, 112808, 3625770, 481239]), 21.1597);

--seed--

--seed-contents--

function sendMessage(route) {

  return route;
}

--solutions--

function sendMessage(route) {
  let totalDistance = route.reduce((a, d) => a += d, 0);

  const delay = (route.length - 1) * 0.5
  const time = totalDistance / 300000
  const total = time + delay;
  return Number(total.toFixed(4))
}