Question

A student walks from his house at a spees of 3km/hr and reaches his school 5 minutes late. The next day he increases his speed by 1 and half km/hr and reaches 5 minutes before school time. How far is the school from his house.​

Answer 1

Answer:25m

Step-by-step explanation:

Let t be the exact time required to reach the school.

Speed1 =3kmph=3×(5/18)m/sec=(5/6)m/sec

Time =(t+5)

Distance(d1)=(5/6)(t+5)...........(1)

Speed =(3+1.5)=4.5 kmph=4.5×(5/18)=(5/4)m/sec

Time=t-5

Distance (d2)=5/4(t-5).......(2)

Solving (1) & (2) we get

(5t+25)/6=(5t-25)/4

Or,4(5t+25)=6(5t-25)

Or,20t+100=30t-150

Or,10t=250

Therefore,t=25

Now, distance to school=(5/4)×(25-5)=5×20/4=100/4=25m