Guna has 8 flavors of ice cream in him parlor. How many options are there for Thilak to pick a one-flavor, two-flavor, three-flavor, four-flavor, five-flavor, six-flavor,seven-flavor or eight-flavor order?
Options:
(A) 223
(B) 395
(C) 448
(D) 774
(E) 835
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8C1 + 8C2+ 8C3+8C4+8C5+8C6+8C7+8C8 = 395. So the answer is: (B).
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From the set of numbers x, y, t, z, s and w, how many different combinations can we have without the t in them? Ex:. (x,y), (x), (w,z,y,x,s), etc and (x,y)=(y,x)
Options:
(A) 10
(B) 14
(C) 15
(D) 16
(E) 31
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Another way: Any letter (x, y, z, w, s) can be included or not. So, we have 2^5 combinations - 1 empty combination = 31 combinations So the answer is: (E).
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A man rows his boat 75 km downstream and 45 km upstream, taking 5 hours each time. Find the speed of the stream?
Options:
(A) 6 kmph
(B) 5 kmph
(C) 2 kmph
(D) 3 kmph
(E) 1 kmph
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Speed downstream = d/t = 75/(5) = 15 kmph
Speed upstream = d/t = 45/(5) = 9 kmph
The speed of the stream = (15 - 9)/2 = 3 kmph So the answer is: (D).
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