Answer:
21
Step-by-step explanation:
They are all the same amount of blocks.
First get a common denominator. (3x*2)
x(x-8) -3(3x)
-------------------
3x^2
x^2 - 8x - 9x
------------------
3x^2
x^2 - 17x
--------------
3x^2
The first one is correct
Let 'x' be the distance from THE far bank where 700 is the distance to the NEAR bank
boat one has travelled 700 (rate = 700/unit time) boat two has travelled x rate = x / unit time
boat one then travels x + 400 more and boat two travels 700 + (700+x -400) more when they meet
The time is the same rate x time = distance distance/rate = time equate the distances divided by the respective rates
(700 + x + 400)/700 = ( x + 700 + (700+x-400) )/x
1100x + x^2 = 1400x + 700000
x^2-300x -700000 = 0 quadratic formula yields x = 1000
One boat travels 700 the other 1000 whe they first meet.....width of river = 700+ 1000 = 1700 m
