A man sold an article for ₹147 by first giving a d% discount on its marked price, and then another discount having the same nominal value (in ₹). If the marked price of the article is ₹420, then what will be the value of d?

A man sold an article for ₹147 by first giving a d% discount on its marked price, and then another discount having the same nominal value (in ₹). If the marked price of the article is ₹420, then what will be the value of d?
एक व्यक्ति ने एक वस्तु को इसके अंकित मूल्य पर पहले d% की छूट और फिर उतने ही सममूल्य (₹ में)  की एक और छूट देकर ₹147 में बेचा। यदि वस्तु का अंकित मूल्य ₹420 है, तो d का मान कितना होगा?