Michael has a science project due. He knew that it would take him 4 hours to complete the project. He needed to spend 50% of his time on his experiment, 40% of his time on his analysis, and 10% on putting his project together.

What is the ratio of time spent putting his project together to the time he spent on the experiment?

A. 2:5
B. 1:9
C. 3:4
D. 1:5

To find the ratio of time spent putting the project together to the time spent on the experiment, we need to determine the amount of time spent on each activity.

Given:
Total time = 4 hours
Experiment time = 50% of total time = (50/100) * 4 = 2 hours
Analysis time = 40% of total time = (40/100) * 4 = 1.6 hours
Putting project together time = 10% of total time = (10/100) * 4 = 0.4 hours

Now, we can find the ratio:
Putting project together time : Experiment time
= 0.4 hours : 2 hours
= 0.4/2 : 2/2
= 0.2 : 1

So, the ratio is 0.2:1, which can also be written as 1:5.

Therefore, the answer is option D. 1:5.

To find the ratio of time spent putting the project together to the time spent on the experiment, we need to calculate the time spent on each activity.

According to the given information, Michael spends 50% of his time on the experiment. To find the amount of time spent on the experiment, we can calculate 50% of 4 hours:

50% of 4 hours = 0.5 * 4 = 2 hours.

Similarly, Michael spends 10% of his time putting the project together, which is equal to 0.1 * 4 = 0.4 hours.

Now we can find the ratio of time spent putting the project together to the time spent on the experiment:

Ratio = Time spent putting the project together / Time spent on the experiment

Ratio = 0.4 hours / 2 hours

Ratio = 0.4 / 2 = 0.2

This means that for every 0.2 hours Michael spends putting the project together, he spends 1 hour on the experiment.

To simplify the ratio, we can multiply both sides by 5:

Ratio = 0.2 * 5 / 1 * 5

Ratio = 1 / 5

So, the ratio of time spent putting the project together to the time spent on the experiment is 1:5.

Therefore, the answer choice is D. 1:5.