अनुपात 13:15 को प्रतिशत के रूप में व्यक्त करने पर वह किसके बराबर होगा? (दशमलव के 2 स्थानों तक पूर्णांकित)

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?