Hi everyone

I am trying to build a JavaScript form using radio buttons and trying to achieve a
watering time calculator using 2 sets of information.
1. 4 different systems
2. 3 different types

All systems + type1 = the variable totals represented below
All systems + type2 = are multiplied by 2
All systems + type 3 = are multiplied by 3.5
If the 'largeplants' check box is selected the total needs to be multiplied by 1.5

The calculateTime function needs to calculate the watering time on click & display an alert box stating the watering time
& The reset button needs to reset the radio buttons.

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Perfect Watering Results</title>

<script>

//Calculate Watering Time for Plants
function calculateTime (){
var radioButton //A radio button
var selectedAnswer = 0; //The number of the selected answer
var system1 = 6; //watering time for sand with jetspray
var system2 = 11;//watering time for sand with sprinkler
var system3 = 17;//watering time for sand wih minisprinker
var system4 = 50; //watering time for sand with dripper

var largeplants = * 1.5; //multiply by 1.5 if checkbox is selected

var type1 //watering time for sand with all systems
var type2 = * 2; //watering time for loam with jetspray/sprinkler/minisprinker/dripper
var type3 = * 3.5;//watering time for clay with jetspray/sprinkler/minisprinker/dripper



// Get the number of the selected answer (1, 2, 3 or 4)
for (var i = 1; i <= 4; i++) {
radioButton = document.getElementById("system" + i);
if (radioButton.checked == true) {
selectedAnswer = i;

// Get the number of the selected answer (1, 2, or 3)
for (var i = 1; i <= 3; i++) {
radioButton = document.getElementById("type" + i);
if (radioButton.checked == true) {
selectedAnswer = i;




}



</script>


</head>

<body>
<h1>Home Garden Watering Guide</h1>
<p>Complete the form below to calculate the recommended watering time for your home garden.<br>
<br>
<br>
<form>
<p>Watering System</p>
<input type="radio" id="system1" name="system" value="JetSpray">
<label for="jet">Jet Spray</label><br>
<input type="radio" id="system2" name="system" value="Sprinkler">
<label for="sprink">Sprinkler</label><br>
<input type="radio" id="system3" name="system" value="MiniSprinkler">
<label for="mini">Mini Sprinkler</label>
<br>
<input type="radio" id="system4" name="system" value="Dripper">
<label for="drip">Dripper</label>
</p>
</p>
</form>
<form>
<p>Click Here if your plants are large
<input type="checkbox" id="largeplants" name="plants"
value="largeplants" onClick=" * 1.5 ">
</form>

<form>
<p>Soil Type</p>
<input type="radio" id="type1" name="soil" value="Sand">
<label for="sand">Sand</label><br>
<input type="radio" id="type2" name="soil" value="Loam">
<label for="loam">Loam</label><br>
<input type="radio" id="type3" name="soil" value="Clay">
<label for="clay">Clay</label></form>
<br><br>
<input type="submit" value="Calculate" id="calculateTime"
onClick="calculateTime" alert("The recommended watering time is "" minutes"> <input type="reset" value="Reset">
</body>
</html>


I know I haven't got through much so any and all help and hits to achieving this will be greatly appreciated.
Also please clarify if I do need to use a loop in this instance

Thanks heaps