Margo's marginal utility of one dance lesson is 100 utils per lesson. Her marginal utility of a

Question:

Margo's marginal utility of one dance lesson is 100 utils per lesson. Her marginal utility of a new pair of dance shoes is 300 utils per pair. The price of a dance lesson is $50 per lesson. She currently spends all her income, and she buys her optimal consumption bundle. What is the price of a pair of dance shoes?