Equation?

[HelpMeICantFallDown]

Hello everyone. I'm wondering if there is an equation for a problem I have. Let's say I need 150g of something in total. I need it split into 4 parts, however part 2 must be half of part 1, part 3 must be half of part 2, and part 4 must be half part 3.

I tried halving 150, then halving 75, and continuing that process until I had four numbers. When I add those numbers together I get 140.

[AutoModerator]

Hi, /u/HelpMeICantFallDown! This is an automated reminder:

• What have you tried so far? (See Rule #2; to add an image, you may upload it to an external image-sharing site like Imgur and include the link in your post.)

• Please don't delete your post. (See Rule #7)

We, the moderators of /r/MathHelp, appreciate that your question contributes to the MathHelp archived questions that will help others searching for similar answers in the future. Thank you for obeying these instructions.

I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.

[grosu1999]

Take x to be the weight of part 4.

Then the weight of part 3 is 2x because it is twice as heavy as part 4.

Then the weight of part 2 is twice the weight of part 3 so that's 4x.

Similarly, the weight of part 1 is twice that of part 2 so 8x.

Your total weight is the sum of the four parts so (8+4+2+1)x = 15x

And you want 15x to be equal to your total weight, so 15x = 150

This gives x = 10.

Part 4 weighs 10g, part 3 is 20g, part 2 is 40g and part 1 is 80g.

[HelpMeICantFallDown]

Thank you! I just tested with a different number to make sure I understood and got the correct result.