Answer:
Billy walked 36 kilometers on the first day
Explanation:
Assume that Billy walked x kilometers in the first day
∵ Billy walked x kilometers on the first day
∵ Each day he walked
of the distance than he walked before
→ That means Billy walked
of x kilometers in the second day
∵
× x = 0.75x
∴ Billy walked 0.75 x kilometers on the second day
∵ Billy walked
of (0.75x) kilometers on the third day
∵
× (0.75x) = 0.5625x
∴ Billy walked 0.5625 x kilometers on the third day
∵ He walked 83.25 kilometers total on the trip
→ Add the distance he walked on the 3 days and equate it by 83.25
∵ x + 0.75x + 0.5625x = 83.25
∴ 2.3125x = 82.25
→ Divide both sides by 2.3125
∴ x = 36
∴ Billy walked 36 kilometers on the first day