Question

the pressure exerted by a certain liquid at a given point varies directly as the depth of the point beneath the surface of the liquid. the pressure at 70 feet is 210 pounds per square inch. what is the pressure at 10 feet? the pressure at 10 feet is pounds per square inch.

Explanation:

Step1: Find the constant of variation

Since pressure $P$ varies directly as depth $d$, we have $P = kd$. Given $P = 210$ when $d = 70$, we find $k$ by substituting into the equation: $k=\frac{P}{d}=\frac{210}{70}=3$.

Step2: Calculate pressure at 10 - feet

Now that $k = 3$, when $d = 10$, we use the equation $P=kd$. So $P=3\times10 = 30$.

Answer:

30