write a general formula to describe variation: S varies jointly with the inverse of the cube root of P and the inverse of the square root of L; S=7 when P=64 and L= 100

Answer:The last option in the question
Step-by-step explanation:
S varied with the inverse of the cube root of P and inverse of the square root of L means S = K/3√P x √L...Inserting the values gives the answer.