Question

challenge #1
if 20 is put into this machine, what will come out?
(image shows a conveyor with 20, then a machine labeled \increase by 50%\ and another labeled \decrease by 50%\)

Explanation:

Step1: Increase 20 by 50%

To increase a number by 50%, we calculate \( 20 + 20\times\frac{50}{100} = 20 + 10 = 30 \).

Step2: Decrease the result by 50%

Now, decrease 30 by 50%: \( 30 - 30\times\frac{50}{100} = 30 - 15 = 15 \).

Answer:

15