Answer:
x = 350
Step-by-step explanation:
x - starting amount
[tex]\frac{2}{7} x[/tex] = after transport
[tex]\frac{1}{5} (\frac{2}{7} x)[/tex] = after sweets
[tex]\frac{1}{5} (\frac{2}{7} x)[/tex] = 20
[tex](\frac{2}{35} x)[/tex] = 20
2x = 700
x = 350