water is being pumped to empty a swimming pool.

At 6 a.m , the water level is 150 cm . Every 2 hours , the water level drops by 30 cm. 
what is the earliest time when the pool will be empt ??

A)10 A.M.
B)11 A.M.
C) 4 P.M. 
D) 5 P.M. 



Answer :

to empty the pool, you need to lower the water level by 150cm. since you can only lower it by 30cm every 2 hours (also same as 15 cm per hour), that means it will take you 10 hours.

150cm*(2 hours)/(30cm) = 150*(1/15) = 150/15 = 10.

6 a.m. + 10 hours = 4 p.m.

So the answer is C.) 4 p.m.

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