Apiano has white keys and black keys in the ratio of 13 : 9. if there are 52 white keys, how many black keys are there?

Aresearch company wants to test the claim that a new multivitamin to improve short term memory. state the objective of the experiment, suggest a population, determine the experimental and control groups, and describe a sample procedure.

Ana drinks chocolate milk out of glasses that each holdof a liter. she has of a liter of chocolate milk in her refrigerator. 10 how many glasses of chocolate milk can she pour?

If value of cos330° is √3/2 then find tan165°.