Janae was vacuuming the narrow hallway in her house. She went 5 feet forwards in the first 4 seconds, then went 3 feet backwards in the next 4 seconds. She continued to do this, forwards 5 feet in 4 seconds and backwards 3 feet in 4 seconds. If she continues in this way, how many seconds will it take her to reach the end of her hallway, which is 15 feet long? 1.

60 seconds

Step-by-step explanation:

Hi!

After she goes forward 5 feet (4 seconds), and the backwards 3 feet (another 4 seconds), the total distance forward she travelled is 2 feet. Then, she moved forward 2 feet in 8 seconds.

Then, as this is repeated, she moves forward 2 feet every 8 seconds. After 7 repetitions she travelled 14 feet, and 56 seconds elapsed. Then she goes forward 5 feet in 4 seconds, and she finaly reaches the end of the hallway

(14 + 5 > 15)

So, in 60 seconds she reached the end of the hallway.