If x varies directly as square root of y and x = 81 when y = 9, Find x when y = 1(frac{7}{9})
-
A.
20(frac{1}{4}) -
B.
27 -
C.
2(frac{1}{4}) -
D.
36
Correct Answer: Option D
Explanation
x (alphasqrt y)
x = k(sqrt y)
81 = k(sqrt9)
k = (frac{81}{3})
= 27
therefore, x = 27(sqrt y)
y = 1(frac{7}{9}) = (frac{16}{9})
x = 27 x (sqrt{frac{16}{9}})
= 27 x (frac{4}{3})
dividing 27 by 3
= 9 x 4
= 36