Charli was a professional classical guitar player until his motorcycle accident that left him disabled. After long months of therapy, he hired an experienced luthier (maker of stringed instruments) and started a small shop to make and sell Spanish guitars. The guitars sell for $700 and the fixed monthly operating costs are as follows:

Rent and utilities	$1,210
Wages and benefits to luthier	2,500
Other expenses	480

Charli's accountant told him about contribution margin ratios and he understood clearly that for every dollar of sales, $0.65 went to cover his fixed costs, and that anything past that point was pure profit.

Charli wishes to earn $4,000 of operating profit each month. Calculate the number of guitars Colin will have to sell to achieve the target profit.