Question

The weight of substance X is halved per minute. In the beginning, the weight of substance X is 5kg.

(a) Find the weight of substance X after 4 minutes.

(b) After how many minutes will the weight of substance X first go below 0.5kg?
Please give your answer as an integer.

EMERGENCY PLEASE HELPPPP

Answer 1

a: 0.3125kg

b: 4

Explanation:

for a we simply calculate 5 * 0.5 ^ 4.
we then see that the weight after 4 minutes is smaller than 0.5kg, but if we go back to 3 minutes (by multiplying our solution to a by 2), giving us 0.625kg, which is now bigger than 0.5kg. meaning 4 minutes is the first whole amount that will give us a weight smaller than 0.5kg.