If 60% of (x - y) = 45% (x + y) and y = k% of x, then 21% of k is equal to:
Answer & explanation
Correct answer: option 4
60% = \(\frac{3}{5}\) , 45% = \(\frac{9}{20}\)
(x – y) × \(\frac{3}{5}\) = (x + y) × \(\frac{9}{20}\)
(x – y) × 4 = (x + y) × 3
4x - 4y = 3x + 3y
\(\frac{x}{y}\) = \(\frac{7}{1}\)
Nw , y = k% of x
1 = k% × 7
k% = \(\frac{1}{7}\)
k = \(\frac{100}{7}\)
21% of k = \(\frac{21}{100}\) ×\(\frac{1}{7}\)
k =3