Answer:
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
<u>Time taken by Samantha</u>
<u>Time taken by Tamara</u>
<u>Equation for difference in time</u>
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
