Let d(t) be the total number of miles Joanna has cycled, and let t represent the number of hours after stopping for a break during her ride. So, d(4) = . This means that after , Joanna .

68

Step-by-step explanation:

Total mile cycled, d(t) ;

d(t) = 12t + 20

At d(4)

t = 4 ;

We have;

d(4) = 12(4) + 20

d(4) = 48 + 20

d(4) = 68

After, 4 hours of cycling, Joanna cycled a total distance of 68 miles

true !

step-by-step explanation: