Answer:
It will take 4 minutes for the balloon to reach an altitude of 57 yards.
Step-by-step explanation:
Initial altitude:
100 1/5 yards = 100 + 0.2 = 100.2 yards.
Decrease per minute:
10 4/5 yards = 10 + 0.8 = 10.8 yards.
So, after t minutes, the height of the ballon is given by:
[tex]h(t) = 100.2 - 10.8t[/tex]
Number of minutes it will take the balloon to reach an altitude of 57 yards.
This is t for which [tex]h(t) = 57[/tex]. So
[tex]h(t) = 100.2 - 10.8t[/tex]
[tex]57 = 100.2 - 10.8t[/tex]
[tex]10.8t = 43.2[/tex]
[tex]t = \frac{43.2}{10.8}[/tex]
[tex]t = 4[/tex]
It will take 4 minutes for the balloon to reach an altitude of 57 yards.