Question

From the same place at 7am 'A' started walking in north at the speed of 4 km/hr. After 1 hour B started cycling in the east at the speed of 8 km/hr. At what time will they be at a distance of 20 km apart from each other?

Answer 1

After 3 hrs A will cover 12 km. and B will cover 16 km.
=>

${12}^{2} + {14}^{2} = 400$
B will travel only 2 hrs