Hello,

Air resistance is constant and same in both cases, so I am ignoring that.

So, we threw a ball with velocity 'u'.

According to formula: v=u+at, we get 0=u+ ( -10 ) ( t1 ) ---> u=10 (t1)

This is because,

• the final velocity is zero, as at max height, it will stop and then come down.
• 10 is the acceleration due to gravity, rounded off.
• t1, as given is time of ascent.

For case 2, v= 0 + 10 (t2) ----> v=10 (t2).

Now , finding ratios by dividing the equations obtained.

t2/t1 = v/u.   This is the required answer.

In reality, t1=t2. But since values are not given in the question, we assume them to be different.

Hope this helps.

Thanks.