The pressure someone experiences as he or she dives deeper and deeper in the ocean increases linearly. On the surface, the pressure is close to 15 pounds per square inch. 33 feet below the surface, the pressure is 30 pounds. If 25000 pounds per sq inch can crush your bones, what depth is extremely dangerous for humans?
Pick.
A) 55522 feet
B) 45522 feet
C) 35522 feet
D) 25522 feet
E) none

Rationale: solution : first , model the pressure ( p ) in terms of depth ( d ) with a linear equation . we will find the equation p = md + b use ( 0 , 15 ) and ( 33 , 30 ) to find m m = 30 - 15 / 33 - 0 m = 15 / 33 = 0.45 p = 0.45 d + b use ( 0 , 15 ) to find b 15 = 0.45 × 0 + b 15 = b p = 0.45 d + 15 25000 = 0.45 d + 15 25000 - 15 = 0.45 d + 15 - 15 24985 = 0.45 d d = 24985 / 0.45 = 55522 feet answer a
Answer: A