Amit and Raman started travelling together in the same direction at 23 km/hr and 35 km/hr receptively

Amit and Raman started travelling together in the same direction at 23 km/hr and 35 km/hr receptively. After 10 hours, Amit increased his speed by 13 km/hr and Raman reduced his speed by 15 km/hr, and reached the destination together. How long the entire journey last?

(a)          7 ½ hrs                                                                           

(b)          17  ½ hrs                                                                            

(c)           12   1/3 hrs                                                                           

(d)          15   1/7 hrs                                                                            

Sol:

A             R

23           35

Distance between them = (35–23) × 10 = 120 km