Question

A car travels $200$ km in $2$ hours and travels $240$ km in next $3$ hours. If the acceleration is constant then the distance it will travel in the next one hour is

• A. $48$ km
• B. $64$ km
• C. $72$ km
• D. $84$ km

Answer 1

The correct option is B $64$ km

Given that acceleration is constant,
$s=ut+\frac{1}{2}a{t}^2\Rightarrow 200=u\times 2+\frac{1}{2}\times a\times 2^2\Rightarrow 100=u+a....\left(1\right)$
and
$\Rightarrow (200+240)=u\times 5+\frac{1}{2}\times a\times 5^2\Rightarrow 880=10u+25a....\left(2\right)$
Solving $\left(1\right)$ and $\left(2\right),$ we get
$a=-8$ and $u=108$
Let the distance travelled in next hour be $s$,
$\Rightarrow 200+240+s=108\times 6+\frac{1}{2}\times (-8)\times 6^2$
$\Rightarrow s=64$ km