Does anyone know the answer what to add and multiply because i really don't get it

If 20% of a number is 35, what is 50% of that number?

Which is the solution to the inequality? 2 3/52 1/15 b< 3 2/15 b> 3 2/15

At the county fair, the baxter family bought 6 hot dogs and 4 juice drinks for $12.90. the farley family bought 3 hot dogs and 4 juice drinks for $8.55. find the price of a hot dog and the price of a juice drink.