Question

PLEASE HELP!!!

Answer 1

The standard formula is: distance = speed x time. From this, we know that speed = distance/time and that time = distance/speed. 

a. If r = speed, then r = distance/time. From the information presented in "a", you cannot calculate Roy's speed. 

b, c. Because the time is the limiting value in the question, use the "time" version of the formula: time = distance / speed 

Because Roy must be at the ceremony in "less than or equal to" 2 hours, we set up an inequality. 
2 <= distance / speed (which = r) 
therefore, 2 <= distance / r 

Because Roy has already travelled 30 miles, he has only 120 miles remaining. 
2 <= 120 / r 

Solve for "speed": 
2r <= 120 
r <= 60 
You must be careful about how you interpret this answer. Remember hat "r" is the MINIMUM speed which solves the equation. Therefore, to make it to the wedding on time, Roy must drive at least 60 mph.
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