Two sisters like to compete on their bike rides. tamara can go 4 mph faster than her sister, samantha. if it takes samantha 1 hour longer than tamara to go 80 miles, how fast can samantha ride her bike?

16 mph

Step-by-step explanation:

You should first form equations related to this information

Given,Tamara can go 4 mph faster than her sister, Samantha

Lets take speed to ride a bike for Samantha to be=  x mph

The speed to ride a bike for Tamara will be= x+4 mph

To cover a distance of 80 miles, Samantha takes 1 hour longer than Tamara

Introduce the formula for time; time=distance/speed=D/S where D is distance in miles and S is speed in miles per hour

Here time Samantha takes to cover a distance of 80 miles is 1 hour more than that taken by Tamara, hence

Time taken by Samantha

Time taken by Tamara

Equation for difference in time

Solve the equation for difference in time to get value of x which is samantha speed

Solve quadratic equation by the quadratic formula where a=1,b=4 and c=-320

x=(-b±√b²-4ac)÷2a

x=(-4±√4²-4×1×-320)÷2×1

Samantha speed is 16 mph

expression #3 is not equivalent. the others are.