Problem with making a histogram [closed]

I have written code that simulates a M/M/1 queue system.

μ = 2; λ = 1.5; n = 5000;
t = 0; served = 0; sList = {}; QList = {};
tOutList = {}; tOutList[[0]] = 0;
Do[X = -Log[Random[]]/λ;
Y = -Log[Random[]]/μ;
t = t + X;
tOut = Max[tOutList[[i - 1]], t] + Y;
AppendTo[tOutList, tOut];
AppendTo[sList, tOut - t];
While[tOutList[[served + 1]] < t,
served = served + 1;
AppendTo[QList, {tOutList[[served]], i - 1 - served}
];
];
AppendTo[QList, {t, i - served}];
,{i, 1, n}];


I tried to use a result from the above code to show the time spent by customers into the system a in histogram.

s = 0;
h =
Histogram[sList,
HistogramScale -> 1,
HistogramCategories -> Table[i, {i, 0, 30, 0.25}]];
p = Plot[(μ - λ)Exp[-(μ - λ)*x], {x, 0, 10}];
Show[h, p]


But I get the following error From Show:

Show::gcomb: Could not combine the graphics objects in Show[Histogram[{0.4337989554392946, 2.3556653158517125,<<

How can I fix this?

Edit: My version of Mathematica is v6

closed as off-topic by MarcoB, m_goldberg, user9660, Yves Klett, JensJun 16 '16 at 18:40

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• "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – MarcoB, m_goldberg, Community, Yves Klett, Jens
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• HistogramScale and HistogramCategories are no longer valid options for Histogram since version 7 of MMA. What version are you using? Where did you get the code? If you remove them, then Show will work fine; it is failing now because Histogram fails and does not return a graphics object. – MarcoB Jun 15 '16 at 19:55
• @MarcoB It may be for the very old Histograms package (pre-v7). – Szabolcs Jun 15 '16 at 19:57
• I forget to mention that my version of mathematica is 6 – ParisL Jun 15 '16 at 19:58
• I think i found the solution. I needed to load the << Histograms;` package – ParisL Jun 15 '16 at 20:20
• Glad that you found that out, but your previous answers confuse me. How could you have got a correct histogram plotted if you didn't have the package loaded at the time? Oh well.. – MarcoB Jun 15 '16 at 21:42