Question 246297
D=RT
72=RT OR T=72/R JIM'S EQUATION.
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60-12=(R-4)T 
48=(R-4)T
T=48/(R-4)
72/R=48(R-4)
48R=72(R-4)
48R=72R-288
48R-72R=488
24R=288
R=288/24
R=12 MPH. WAS JIM'S RATE.
12-4=8 MPH. WAS JACK'S RATE. ANSWER. B)
PROOF:
72/12=48/8
6=6