need help please

Question

Estimate the cost of roofing a building if the roof area is 4200 square feet. The shingles will cost $45 per square and the labor charge is $38 per square. (One square of shingles covers 100 square feet.)

Answer 1

4200 sq ft requires 42 shingle squares at a total cost of 42*$45=$1,890. If the cost of labour is $38 per shingle square, the total cost of labour is 42*$38=$1,596. Total cost of job=$3,486.