[tex]Let \ the \ number \ be : \ \ x \\\\Then \frac{2}{5} \ of \ the \ number \ is: \ \ \frac{2}{5 }x\\\\ x+\frac{2}{5}x=210 \\ \\ 1\frac{2}{5}x=210\\\\\frac{7}{5}x=210\ \ | \ multiply\ both\ sides\ by\ \frac{5}{7}\\\\x=210\cdot \frac{5}{7}=30\cdot 5=150\\ \\Answer: \ The \ number \ is\ 150 [/tex]
