Question

amanda, bryan, and colin are in a book club. amanda reads twice as many books as bryan per month and colin reads 4 fewer than 3 times as many books as bryan in a month. in 4 months the number of books amanda reads is equal to 5/8 the sum of the number of books bryan and colin read in 4 months. how many books does each person read each month?

Answer 1

Please see below solution:
Let x = number of books that Bryan reads2x  for amanda = Amanda 3x - 4 for Colin  Amanda = 5/8(Bryan + Colin)2x = 5/8(x+3x-4)2x = 5/8(4x-4)

[16x = 5(4x-4)]816x = 20x - 20Subtract 20x from each side-4x =-20-4x/-4= -20/-4 divide -4 to eliminate the -4 in -4xx = 5
Therefore:
Bryan reads 5 books a month.
Since Amanda reads twice as many books a Bryan read so Amanda 10 books a month. 
And Colin 11 books a month. 3(5) - 4 = 11