John had 77 apples he gave 20 to alex and 15 to jack how many apples does john have left

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Abag contains 4 red, 7 blue and 5 yellow marbles. event a is defined as drawing a yellow marble on the first draw and event b is defined as drawing a blue marble on the second draw. if two marbles are drawn from the bag, one after the other and not replaced, what is p(b|a) expressed in simplest form? a. 7/16 b. 7/15 c. 14/16 d. 14/15

What is the value of n in the equation -1/2(2n+4)+6=-9+4(2n+1)