Question

Henry spent 45% of his savings on a new television set that
cost $810. How much money did he have in his savings
account before he bought the new TV?​

Answer 1

45% of some number x is 810.

We can rewrite this as

$x\cdot0.45=810$

And solve for x

$x=\dfrac{810}{0.45}=1800$

He had $1800 before he had bought new TV.