When amy exercises in her fitness for 1 hour she burns a total of 475calories if she burns 9 calories a minute jogging on the treadmill and then burns 6.5 calories a minute pedaling on stationary bicycle how many minutes of hour does she spend exercising on bicycle

  26 minutes on the bicycle

Step-by-step explanation:

Let t and b represent the number of minutes on the treadmill and bicycle, respectively. The problem statement tells us two ways to relate these values.

  t + b = 60 . . . . . Amy exercises a total of 60 minutes (1 hour)

  9t +6.5b = 475 . . . . . she burns a total of 475 calories

Since we want to find the value of "b", we can use the first equation to write an expression that will substitute for t.

  t = 60 -b

  9(60 -b) +6.5b = 475

  540 -2.5b = 475 . . . . . . simpify

  -2.5b = -65 . . . . . . . . . . subtract 540

  b = 26 . . . . . . . . . . . . . . . divide by -2.5 (equivalently, multiply by -2/5)

Amy spends 26 minutes exercising on the bicycle.

ad = ae + ed = y + 7

similar triangles therefor

ac/ab = ad/ae

6/4 = (y + 7) / y

cross multiply

6y = 4(y + 7)

6y = 4y + 28

2y = 28

y = 14

step-by-step explanation: