Answer:
each plan is 3/4 hours
Step-by-step explanation:
We can write equations for the total workout time on each day.
5A +3B = 6
7A +9B = 12
Subtracting the second equation from 3 times the first gives ...
3(5A +3B) -(7A +9B) = 3(6) -(12)
8A = 6 . . . . . . . . . simplify
A = 6/8 = 3/4
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Using the simplified equation, we can substitute for 6 in the first equation.
5A +3B = 8A
3B = 3A . . . . . subtract 5A
B = A . . . . . . . divide by 3
B = 3/4
Each of Jessica's workout plans takes 3/4 hours.
