Question

On the first day of training, Aretha holds a plank position for 30 seconds. She increases her time by 20% each day. What is the first day on which Aretha holds a plank for over a minute? Show your work

Answer 1

5 th day

Explanation:

Given :

1st day :

Time = 30 seconds

Time increases by 20% each day :

2nd day = 20% * 30 = (1.20 * 30) = 36 seconds

3rd day = 1.20 * 36 = 43.2 seconds

4th day = 1.20 * 43.2 = 51.84 seconds

5th day = 1.20 * 51.84 = 62.208

First day Aretha hold a plank for over 1 minute is the 5th day