Question

2019 Chapter Sprint Round, #20

Answer 1

Answer:

$Speed\ of\ car=38\ km/h$

Step-by-step explanation:

Distance Covered by Horse:

$Speed\ of\ horse=50\ km\h=50\times \frac{1000}{60}\ meter/ minute\\\\Speed\ of\ horse=\frac{2500}{3}\ meter/minute\\\\Distance\ covered\ in\ 4\ minutes=speed\times time=\frac{2500}{3}\times 4\\\\Distance\ covered\ in\ 4\ minutes=\frac{10000}{3}\ meters$

Distance covered by Car:

$Let\ speed\ of\ car=x\ meter/minute\\\\time=4\ minutes\\\\Distance\ covered=speed\times time=4\times x=4x$

$Distance\ covered\ by\ horse=Distance\ covered\ by\ car+800\\\\\frac{10000}{3}=4x+800\\\\4x=\frac{10000}{3}-800\\\\4x=\frac{7600}{3}\\\\x=\frac{7600}{3\times 4}\ meter/minute\\\\x=\frac{7600}{3\times 4}\times \frac{60}{1000}\ km/h\\\\x=38\ km/h$