The average revenues of 7 consecutive years of a company is Rs 83 lakhs. If the average of first 4 years is Rs 78 lakhs and that of last 4 years is Rs 90 lakhs, find the revenue for the 4th year.
The ten's digit of a 2-digit number is greater than the units digit by 7. If we subtract 63 from the number, the new number obtained is a number formed by interchange of the digits. Find the number.