किसी संख्या के 80% और 65% के बीच का अंतर 135 है। उसी संख्या का 49% क्या होगा?

A person saves 90% of his income. If his expenditure is ₹520, find his income (in ₹).

By how much is 30% of 60 greater than 25% of 40?

By how much is 30% of 50 greater than 35% of 30?