You know the cost of 10 pencils, so multiply the cost of 10 pencils by 3 to find the cost of 30 pencils.
10 pencils: $0.59
30 pencils: $0.59 * 3 = $1.77
The 10% discount won't be applicable for your purchase of 30 pencils because it applies to a purchase of 3 dozen, or 36 pencils.
So your answer for the cost of 30 pencils is $1.77.
