A number is added to 212 and the sum is multiplied by 412. Then 3 is added to the product and the sum is divided by 115 which gives the quotient as 25. What is the number?
Let the number be x. Then,
412(x+212)+3115=25⇒92(x+52)+365=25
⇒9x2+454+3=25×65=30⇒9x2=30−574⇒9x2=634
⇒x=(634×29)=72=312