Carlos's utility function is

u$($a$,$b$)=$a$+2$b$,$

where a is his consumption of artichokes and b is his consumption of broccoli.

Laura's utility function is

u$($a$,$b$)=$min$\{$a$,2$b$\}.$

Laura initially has $60$ artichokes and no broccoli. Carlos initially has $60$ broccoli and no artichokes.

In this economy, in competitive equilibrium, the ratio of the price of artichokes to the price of broccoli must be $($round to one decimal if necessary$).$