When two fractions refer to the same whole and have the same denominator explain why you can compare only the numerator

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

If angle b measures 25°, what is the approximate perimeter of the triangle below? 10.3 units 11.8 units 22.1 units 25.2 units