Mary deposits money in a bank that compounds interest at i effective per annum.

At the same time, sam deposits the same amount as mary in another bank that compounds interest at (i+0.1) effective per annum. the end of 5 years, sam has as much in his accounts as mary will have at the end of 10 years. Determine i.

(due a decimal number, rounded to the nearst 10000th for example 0.1234)