5. After 6 hours, the concentration is halved. After 12 hours, it will be quartered. If the original concentration is 200 nmol, a quarter is 50 nmol.
14. The population doubles after 3 hours, and a day is 24 hours. That means that the original population should be multiplied by
, or
. 3 million times
is 3 * 256 million, or 768 million.
15. The concentration is halved every 8 hours and the original concentration is 100 nmol. So now, how many times do you halve 100 to get to 12.5?
100/2 = 50, 50/2 = 25, 25/2 = 12.5. That's three times. 3 * 8 is 24 hours, or 1 day.
Answer:


= 2 × 625 – 5 × 125 + 25 + 3 × 5 + 2
=1250 – 625 + 25 + 15 +2
= 1292 – 625
= 667
Answer: Maggie is 7 years old.
7 . 2 = 14
14-3=11
11+7=18
Hope this helps!