Problem: Steph likes basketballs and sneakers. He has well-defined indifference curves, which are bowed towards the origin and do not intersect either axis. The price of basketballs is $30 and the price of sneakers is $90. If the Steph's marginal rate of substitution of sneakers for basketballs (marginal utility of sneakers / marginal utility of basketballs) is 2, is he consuming an optimal bundle? If not, should he buy more basketballs or sneakers? can you provide the Formula that you will use?