Keith asked 30 people whether they knew how to play whist or dominoes. fifteen of them knoew how to play whist and 20 knew how to play dominoes. five people did not know how to play either game. create a venn diagram to determine how many knew how to play both games.

Two farmers pay a total rent of $140 for a pasture. the first farmer placed $4 oxen in the pasture, and the second farmer placed $30 sheep in the pasture. the farmers split the rent based on the proportion of the pasture eaten by their own animals that month. how much should the first farmer pay, if 1 ox eats as much as 10 sheep in a month?