How many different arrangements are possible to place seven different books on a shelf if all three math books must be placed next to each other? Select the correct option:
A) 120	B) 148	C) 360	D) 540	E) 720
Let the 3 math books be M1,M2,M3 while the rest be A,B,C,D for a total of 7 different books.   Consider 3 math books to be 1 collective item (=M1M2M3 = M , as they need to be together). Thus, number of arrangements of 3 different books (M1M2M3)= 3P3 = 3!   Total number of arrangements of M,A,B,C,D = 5P5= 5!   Thus, The total possible arrangements will be : M1M2M3 ABCD = 5!*3! = 720, 720 is the correct answer
<result>E</result>
How many different arrangements are possible to place seven different books on a shelf if all three math books must be placed next to each other?