17% of 99 is 16.83. Since that's only the distance it goes in one minute we have to multiply that by 3. 16.83 × 3 = 50.49. Since the elevator is moving down then it will be negative. The answer will be -50.49 meters.
Equations:
m = k + 5
k = s + 2
m + k + s = 30
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Substitute for "m" and for "s"::
k+5 + k + k-2 = 30
3k +3 = 30
3k = 27
Kirsty has 9 marbles
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Mina has 9+5 = 14 marbles
Seb has 9-2 = 7 marbles
I a pretty sure it is 228,000 but i am not sure.