Answer:
Speed of Jennifer on Sunday [tex]=45[/tex] mi/hr
Step-by-step explanation:
Let speed of Jennifer on Saturday be x mi/hr
On Saturday morning, it took Jennifer 3.6 hours to drive to her mother's house for the weekend.
Distance travelled by Jennifer on Saturday = Speed × Time [tex]=3.6x[/tex] miles
Speed of Jennifer on Sunday = [tex](x-5)[/tex] mi/hr
On Sunday evening, due to heavy traffic, it took Jennifer 4 hours to return home.
Distance travelled by Jennifer on Sunday = Speed × Time [tex]=4(x-5)[/tex] miles
As distance is obviously same on both Saturday and Sunday,
[tex]3.6x=4(x-5)\\3.6x=4x-20\\20=4x-3.6x\\20=0.4x\\x=\frac{20}{0.4}\\ x=50[/tex]
Therefore,
Speed of Jennifer on Sunday = [tex](50-5)=45[/tex] mi/hr
