Answer :

HolmesNWatson
To work out the profit, firstly, you have to work out the cost of buying them, which is $15 multiplied by 100, which is $1500. You then have to work out what he sold them all at, which is $29.99 multiplied by 100, which is $2999. You then have to subtract $1500 from $2999, giving you $1499. Therefore, Ace made $1499 in profit. Hope this helps :)
SchwarzschildRadius
So, assuming that there is no overhead, we are finding the gross profit.

The profit will be
selling price - cost = gross profit or x
selling price - cost = x

1. selling price = $29.99 (no rounding)

2. cost = $15

selling price - cost = x

29.99 - 15 = x

Collect Like Terms
14.99 = x

Ace Landscaping made a gross profit of $14.99 per shovel.
Since they sold 100 shovels, their profit is increased 100-fold.

$14.99(100) = total gross profit

$1499 = total gross profit

Ace Landscaping grossed $1499. (A LOT) (RIP-OFF :P)