Hot air balloon question

[tigwer]

Not so sure in which category this fits into, so I decided to post this here.
I've been revising tests online and have found this question in which I'm not so sure how to workout.

Any help will be appreciated!

 

[topsquark]

Please show whatever work you've been able to do on this. We can help you better that way.

Hint: Use the first two pieces of information to find K. What do you do then?

-Dan

 

[tigwer]

Please show whatever work you've been able to do on this. We can help you better that way.

Hint: Use the first two pieces of information to find K. What do you do then?

-Dan

So far I've managed to find K, since you are given the first distance it went in a minute.
So I've done:
1040 = (K * 1200) +20
K = 0.85

I've tried substituting this into the equation but now am not sure on what to do.
So I'm stuck on h(3+1) = 0.85*h(3)+20

 

[Deleted member 4993]

So far I've managed to find K, since you are given the first distance it went in a minute.
So I've done:
1040 = (K * 1200) +20
K = 0.85

I've tried substituting this into the equation but now am not sure on what to do.
So I'm stuck on h(3+1) = 0.85*h(3)+20

So after 1 minute (@ 9:16) the balloon is at 1040

height at @9:17 = K*1040+20 = 904

height at @9:18 =??