Question

Can u guys PLEASE answer this question ASAP. A fat cat that was initially 12 kg reduces its weight by 10% each month. How long does it take for the cat to be at least 6 kg lighter than its original weight? Give your answer as a whole number of months.

Answer 1

Answer:

It takes at least 7 months for the cat to be at least 6 kg lighter than the original weight.

Step-by-step explanation:

Use exponential decay formula:

A = P (1-r)t

A = amount decreased to

P = original amount

r = rate of decrease

t = time

 

6 ≥ 12 (1-0.10)t      divide both sides by 12

0.5 ≥ (0.9)t            take log of both sides

log (0.5) ≥ log (0.9)t     power rule of logs lets the exponent t drop to front of log to become a factor

log (0.5) ≥ t log(0.9)     divide both sides by log(0.9) which is negative so reverse the inequality sign

log (0.5) / log (0.9) ≤ t     use calculator

6.57 ≤ t

 

It takes at least 7 months for the cat to be at least 6 kg lighter that original weight.

 

check:

12 (0.9)7≈ 5.73

12 (0.9)6 ≈ 6.37