Question 756558
How many ways can you arrange 2 geometry, 4 algebra, 5 history, and 3 physics textbooks by subject
<pre>
{{{(matrix(12,1,
THE,NUMBER,OF,WAYS,TO,SELECT,THE,ORDER,OF,THE,4,SUBJECTS))}}}{{{TIMES}}}{{{(matrix(13,1,
THE,NUMBER,OF,WAYS,TO,SELECT,THE,ORDER,OF,THE,2,GEOMETRY,BOOKS))}}}{{{TIMES}}}{{{(matrix(13,1,
THE,NUMBER,OF,WAYS,TO,SELECT,THE,ORDER,OF,THE,4,ALGEBRA, BOOKS))}}}{{{TIMES}}}{{{(matrix(13,1,
THE,NUMBER,OF,WAYS,TO,SELECT,THE,ORDER,OF,THE,5,HISTORY,BOOKS))}}}{{{TIMES}}}{{{(matrix(13,1,
THE,NUMBER,OF,WAYS,TO,SELECT,THE,ORDER,OF,THE,3,PHYSICS,BOOKS))}}}{{{""=""}}}

4!×2!×4!×5!×3! = (4×3×2×1)(2×1)(4×3×2×1)(5×4×3×2×1)(3×2×1) = 24×2×24×120×6 = 829440 ways

Edwin</pre>