Correct option is: (4) 105
Given:-
Two-fifth of one-third of three-seventh of a number is 15.
\(\frac{2}{5} \ of \ \frac{1}{3} \ of \ \frac{3}{7} \ of \ x = 15\)
\(\frac{2}{5} \times \frac{1}{3} \times \frac{3}{7} \times x= 15\)
\(\frac{2x}{35}=15\)
\(2x = 15 \times 35\)
\(x = \frac{15 \times 35}{2}\)
\(\therefore \ x = 262.5\)
Now,
40% of 262.5
\(=\frac{40}{100} \times 262.5\)
\(= \frac{10,500}{100}\)
\(=105\) .
