Question

Explain why a change from 20 to 40 is a 100% increase, but a change from 40 to 20 is a 50% decrease. I don't under stand it

Answer 1

Explanation:

40 to 20 is a 50% decrease because you are halving it

20 to 40 is a 100% increase because you are adding 100% of 20 to 20 and you get 40.

Answer 2

I hope this helps :)

Explanation:

For 20 to 40, how much are you adding to your first number (20) to get your second number (40)?

• You are adding 20 to your original number, which is the same amount
• Since you add the same amount to your original number (100% of your original number,) it is a 100% increase.
• For example: a 50% increase from 20 would be adding 50% of your original number (20) to the original number (e.g. 20 + (20/2) = 30 --> 50% increase)

For 40 to 20, how much are you decreasing from your first number (40) to get your second number (20)?

• You are subtracting 20 from your original number, which is half of the amount
• Since you subtract half (50%) of your original number, it is a 50% decrease
• For example: a 50% decrease from 30 would be taking away 50% of your original number (30) (e.g. 30 - (30/2) = 15 --> 50% decrease)