The Slate Above the Hearth

The innkeeper at the Kettle & Crow chalks every sale onto the slate above the hearth, and her hand is tired. She wants each line written the same way, every time.

Write slateLine(name, count, price).

• name is a string: the name of the good, written exactly as it should appear.
• count is a non-negative integer: how many were sold.
• price is a non-negative integer: the cost in coins of a single one.

Let the total be count multiplied by price. Return a single string of the form:

"<count> x <name> = <total> coins"

with single spaces exactly where shown, a lowercase x between the count and the name, and no leading or trailing spaces. The last word is coin when the total is exactly 1, and coins for every other total.