The average revenues of 7 consecutive years of a company is Rs 79 lakhs. If the average of first 4 years is Rs 74 lakhs and that of last 4 years is Rs 86 lakhs, what is the revenue for the 4th year?
A 600 metres long train is running at the speed of 81 km/hr. If it crosses a platform in 40 seconds, then what is the length of the platform (in metres)?