"y varies directly as x" means y = kx
you do not know what k is yet, other than that it is some constant number.
Now plug in the given values, y=12 when x=4, in the equation
12 = 4k
=> k = 3
Now rewrite the equation with the k value you just found
y = 3k
Substitute 18 in place of x
y = 3(18)
y = 54
The distance covered by the hare and the tortoise in t seconds are 8t and 5t respectively. (Simple Speed-Distance-Time relation)
The tortoise gets a 510m headstart so at t=0 is 1490m.
The functions representing the distance of both of them from the finish line is,
F(x)=2000-8t,. for hare
G(x)=1490-5t,. for tortoise
Associative Propety
(a + b) + c = a + (b + c)
Capacity of the pool = 30 x 20 x 5 = 3000 ft³
Amount of water already filled = 30 x 20 x 4 = 2400 ft²
Amount of water needed to full the pool = 3000 - 2400 = 600 ft²
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Answer: 600 ft² of water is needed to fill up the pool.
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