Jonah is playing a video racing game called Checkpoint. The speed of Jonah’s car is recorded four times during one lap. At the first checkpoint, his speed is 80 miles per hour. At the second checkpoint, his speed has reduced by 5%. At the third checkpoint, Jonah’s speed has increased 1/4 by the speed from the previous checkpoint. At the fourth checkpoint, his speed decreased by 20% compared with the third checkpoint. What is Jonah’s net change in speed between the first and fourth checkpoints?

Question

Jonah is playing a video racing game called Checkpoint. The speed of Jonah’s car is recorded four times during one lap. At the first checkpoint, his speed is 80 miles per hour. At the second checkpoint, his speed has reduced by 5%. At the third checkpoint, Jonah’s speed has increased 1/4 by  the speed from the previous checkpoint. At the fourth checkpoint, his speed decreased by 20% compared with the third checkpoint. What is Jonah’s net change in speed between the first and fourth checkpoints?

mathstudent55 · Answer

1st checkpoint: 80 mph
2nd checkpoint 80 mph - 5% of 80 mph
What is the speed at the second checkpoint?