Two Vehicles Moving in the Same Direction

1. 1The motorcycle is 12 km aheadFrom 07:00 to 08:00, the motorcycle travels 12 × 1 = 12 km and reaches 12 km from AA. The car starts at 0 km.12 − 0 = 12 km
2. 2In 1 hour, how much farther does the car go?Place the two one-hour distances side by side: the motorcycle covers 12 km, the car covers 36 km. The first part of the car's distance only keeps up with the motorcycle; the extra 24 km is what actually shrinks the gap.36 − 12 = 24 km/h
3. 3The 12 km gap closes in 0.5 hoursTake the gap, divide by the difference in speeds: 12 ÷ 24 = 0.5 hours. Watch the gap counter run down to 0 as the two vehicles close in.12 ÷ 24 = 0.5 h
4. 4They meet at 08:30The car catches the motorcycle at 08:30, at a point 18 km from warehouse AA.08:00 + 0.5 h = 08:30 · 18 km from AA
5. 5Check the AnswerMeasure from warehouse AA two ways: the car travelled 18 km directly; the motorcycle had a 12 km head start and then travelled 6 km more. Both must land on the same meeting point: 18 km.Car: 18 km = Motorcycle: 12 + 6 km ✓
6. 6Wrap-up: add or subtract the speeds?One road, two kinds of chase: moving toward each other, the gap closes by the sum of the speeds; moving in the same direction, it closes only by the difference. When a new problem arrives, ask yourself: are the two vehicles moving in the same direction or toward each other? Who is ahead?Toward each other → ADD · Same direction → SUBTRACT

Change the numbers to test the engine with any sum & difference problem: