Tom got 15 questions right on a test and scored 75%. How many questions were there total on Tom's test?

(a) calculate the molarity of a solution that contains 0.0345 mol nh4cl in 400 ml of solution. (b) how many moles of hno3 are present in 35.0 ml of a 2.20 m solution of nitric acid? (c) how many milliliters of 1.50 m koh solution are needed to supply 0.125 mil of koh ?

(urgent ) use pi 3.14 to estimate the circumference of the circle to the nearest hundredth middle is 4in (urgent )

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)