In the following items, each passage consists of six sentences. The first sentence (S1) and the final sentence (S6) are given. The middle four sentences in each have been removed and jumbled up. These are labelled P, Q, R and S. You are required to find out the proper sequence of the four sentences and mark accordingly on the Answer Sheet. 

S1: James Watt used the power of steam to drive machines. 
P: With petrol engines people were able to build motor cars and aeroplanes. 
Q: Then, many years later, the petrol engine was invented. 
​R: These provided quicker means of traveling. 
S: His invention was used later by other clever men to give us the railway engine.  
S6: The jet engine is relatively more recent.