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Question

There are white, blue, and red boats in a marina. Two-thirds of the boats in the marina are white, 4/7

 of the remaining boats are blue, and the rest are red. If there are 15 red boats, how many boats are in the marina?

Answer 1

15 red

2/3 white

4/7 of 1/3 = 4/21 are blue

1-2/3- (1/3)(4/7)= 1-14/21-4/21

= 1-18/21= 1-6/7=1/7 red

7x15 = 105 total boats

2/3 x 105 = 70 white

4/21 x 105 = 20 blue

15 red

70+20+15 = 105 total boats