SOLUTION: Jenny can run 2 miles per hour more than twice as fast as bob can walk. if bob can walk 3 miles in the same time it takes Jenny to run 7.2 miles, what is bobs walking speed?
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Question 1136937: Jenny can run 2 miles per hour more than twice as fast as bob can walk. if bob can walk 3 miles in the same time it takes Jenny to run 7.2 miles, what is bobs walking speed? Found 2 solutions by addingup, ikleyn:Answer by addingup(3677) (Show Source):
You can put this solution on YOUR website! J = 2B + 2
3B = 7.2J
3B = 7.2(2B + 2)
3B = 14.4B + 14.4
3B - 14.4B = 14.4
11.4B = 14.4
B = 14.4/11.4
B = 1.26
Bob walks at a speed of 1.26 miles per hour
J = 2B + 2 (1) ("Jenny can run 2 miles per hour more than twice as fast as bob can walk.")
= (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
= .
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 = = 5.
Thus Bob walks at the rate 5 miles per hour.
Then Jenny runs at 2B+2 = 2*5 + 2 = 12 miles per hour.
Answered and solved.
Notice that the solution and the answer by the other tutor both are wrong.
