A truck covers a distance of 384 km at a certain speed. If the speed i

1.	A truck covers a distance of 384 km at a certain speed. If the speed is decreased by 16 km/h. it will take 2 hours more to cover thesame distance. 75% of its original speed (in km/h) is:
Answer» Answer: 75% of original speed is =48 km /hr Step-by-step explanation: Given, TRUCK distance covered 384 km. Speed of truck is =x km/hr If speed of truck is decrease by 16 km/hr it will take 2 hours more to cover the same distance. Find out the 75% of original speed of truck. Solution, New speed of truck is =(x-16)km/hr $384/\left ( x-16 \right )-384/x=2$ $384\left ( 1/\left ( x-16 \right )-1/x \right )=2$ $384\left ( x-\left ( x-16 \right ) \right )/\left ( x\left ( x-16 \right ) \right )=2$ $384\left ( x-x+16 \right )=2\left ( x^{2}-16x \right )$ $192\times 16=x^{2}-16x$ $x^{2}-16x-3072=0$ $x^{2}-64x+48x-3072=0$ $x\left ( x-64 \right )+48\left ( x-64 \right )=0$ $\left ( x-64 \right )\left ( x+48 \right )=0$ $x-64=0$ $x=64$ km/hr or $x+48=0$ $x=-48$ km/hr (Reject it because x=-48 km/hr NEVER possible .Speed cannot be NEGATIVE) Calculate 75% of original speed = $x\times 75%$ % = $x\times 3/4$ $64\times 3/4=48km/hr$