Somebody know this math
plz help me

Mr. vector door is buying two new cowboy hats all together the hats cost $75.12 the second heart cost twice as much as the first hat what is the price of the more expensive at round to the nearest hundredth

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities

Calculate the effective quarterly compound interest rate equivalent to a 1% of monthly compound interest rate.