PriyamRathor wrote:
During Lunch at their favourite place, Karishma and Shubham enter a racing bet. Karishma bets that even if she starts driving 4 minutes after Shubham , she will beat him by 4 miles . Karishma wins the bet after t minutes of driving and stops to wait for Shubham .If both Shubham and Karishma drive at constant speeds throughout , does Shubham drive more than 22 miles till the time Karishma stops ?
1. Shubham drives 0.25 miles per minute slower than Karishma does
2. Karishma is 3 miles behind Shubham when she starts
Karishma travels for t minutes and covers d miles.
Shubham travels for t+4 minutes and covers d-4 miles in it.
1. Shubham drives 0.25 miles per minute slower than Karishma does
So difference in speed in miles per minute = K-S=0.25
Also, the last 4 miles are covered by Shubham after Karishma has finished race is 4/0.25 = 16 minutes.
Thus S finishes entire d in t+4+16 minutes.
2. Karishma is 3 miles behind Shubham when she starts
So Shubham’s speed is 3 miles in 4 minutes as he has traveled for 4 minutes. => 3/4 or 0.75 miles per minute.
Combined
S=0.75 miles per minute. So d=0.75(t+20)
K=0.75+0.25 or 1 mile per minute. So, d=1*t
t=0.75(t+20)
0.25t=15 or t=60 minutes.
Thus, d=60*1 or 60 miles, and Shubham has traveled 4 miles less when Karishma stops.
Sufficient as answer is YES.
C