Question

7. If Speed = 25 Km/h and Time = 10 h​

Answer 1

Let the speed be x km/hr

Speed = distance/ time

time= distance / speed = 25/x

When the speed is increased by 8kms/hr the new speed will be (x+8) km/hr

Time required for this speed will be 25/x+8

25/x-25/(x+8) = 10

25((x+8) - 25x/ x(x+8) =10

10x^2+80x-200=0

x^2+8x-20=0

x^2+10x-2x-20=0

(x+10)=0 or x-2=0

x= -10 or x=2

spped can not be negative so the original speed of the car was 2km/hr.