Question 1136937
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J = 2B + 2      (1)    ("Jenny can run 2 miles per hour more than twice as fast as bob can walk.")

{{{3/B}}} = {{{7.2/J}}}        (2)    {The "time" equation, literally translated and written as it is given)



From equation (1), substitute the expressin J = 2B + 2 into equation (2). You will get


{{{3/B}}} = {{{7.2/(2B +2)}}}.


Cross multiply; then simplify step by step and solve for B :


3*(2B + 2) = 7.2B

6B + 6     = 7.2B

6 = 7.2B - 6B

6 = 1.2B     ===============>  B = {{{6/1.2}}} = 5.


Thus Bob walks at the rate 5 miles per hour.


Then Jenny runs at  2B+2 = 2*5 + 2 = 12 miles per hour.
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Answered and solved.


Notice that the solution and the answer by the other tutor both are wrong.