C = # of carpenter hrs , b = # of blacksmith hrs
c + b = 30...c = 30 - b
20c + 25b = 690
20(30 - b) + 25b = 690
600 - 20b + 25b = 690
-20b + 25b = 690 - 600
5b = 90
b = 90/5
b = 18 <== hrs worked as blacksmith
c + b = 30
c + 18 = 30
c = 30 - 18
c = 12 <== hrs worked as carpenter
First covert them to fractions with the same denominator so you can compare them (9/12 and 4/12), then subtract the numerators, and not the denominators (9/12-4/12), then whatever you get is the answer (5/12). If you can, simplify.
Answer: 8.94427
Step-by-step explanation: using the Pythagorean theorem which is A squared plus B squared equals C squared you can find this
17 • 4 is the equation that represents the product