i dont understand can you help me

Answer:
[tex] \frac{9}{10}x = 18[/tex]
[tex] \frac{2}{3}y = 18[/tex]
we can make these two equations.
solve for x and y:
[tex]\frac{9}{10} x \div \frac{9}{10} = 18 \div \frac{9}{10} [/tex]
x = 20
[tex] \frac{2}{3} y + \div \frac{2}{3} = 18 \div 2 \frac{2}{3} [/tex]
y = 27
The total number can be calculated by:
x + y = 20 + 27 = 47
Your answer:
47
which is D.