What would be the cost of 30 pounds of mushrooms

you didn't give us the cost of the mushrooms but,

Step-by-step explanation:

If it is a even number then multiply 30 with the price.

check the picture below.

well, the angle at the vertex d is clearly not a right-angle, let's check for the one at the vertex f which does look like,   however if it's indeed, that means ef is perpendicular to df, in which case their slopes will be negative reciprocal of each other.

so the negative reciprocal of the slope of ef is 1, however the slope of df is not 1, is 1/2, so nope, they're not perpendicular lines.