Half life and doubling time

The population of turtles is doubling every 3 months. If there are 400 turtles now, how many will there be in 2 years?

• y = 104,200

• y = 120,400

• y = 102,400

• y = 124,000

A bacterial colony doubles in size every 6 hours. There are 90 bacteria present initially. Estimate the population size after 80 hours. What is the answer?

• 982,914

• 914,928

• 928,914

• 914,914

Tags

CCSS.HSF.LE.A.4

James' 70 in. giant peach doubles in size every week. Write an expression that would represent how big the peach is after 5 weeks.

• 2,240

• 2,420

• 2,024

• 2,042

Tags

CCSS.HSF.BF.A.2

The population of a bacteria is doubling every 3 minutes. If there are 50 bacteria now, how many will there be in 7 minutes?

• Approximately 152 bacteria

• Approximately 352 bacteria

• Approximately 252 bacteria

• Approximately 452 bacteria

Tags

CCSS.HSF.LE.A.4

Bacteria can multiply at an alarming rate when each bacteria splits into two new cells, thus doubling. If we start with only one bacteria which can double every hour, how many bacteria will there be after 24 hours?

• 16,777,261

• 16,727,216

• 16,777,216

• 16,277,716

Tags

CCSS.HSF.LE.A.4

If 10 mg of iodine-131 is given to a patient, how much is left after 24 days? The half-life of iodine-131 is 8 days.

• 1.25mg

• 1.52 mg

• .125 mg

• 125 mg

Tags

CCSS.HSF.LE.A.4

The half-life of strontium-90 is 25 years. How much strontium-90 will remain after 100 years if the initial amount is 4.0 g?

• 2.5 g

• 250 g

• 0.52 g

• 0.25g

Tags

CCSS.HSF.LE.A.4

If the half-life of uranium-232 is 70 years, how much will remain after 90 years? The starting amount is 225 mg. Round answer to nearest tenth.

• 92.8 mg

• 92.3 mg

• 93.3 mg

• 93.2 mg

Tags

CCSS.HSF.LE.A.4

An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? 

• 0.5 mg
• 0.25 mg
• 0.125 mg
• 0.0625 mg

Tags

CCSS.HSF.LE.A.4