David earned a fixed salary each month. In January, he spent $400 and saved the rest. In February, he spent 10% more and his savings dropped by
20%. What was David's savings in January?

$200.

Step-by-step explanation:

Let his fixed monthly salary be x dollars.

Then he saved x-400 dollars in January.

He spent 10% more in February which is $440 so his savings were x-440 dollars, which is 0.20 less than in January. So we have the equation:

(x - 400)  - (x - 440) = 0.20(x - 400)

0.80(x - 400) =  x - 440

0.8x -  320 - x = -440

-0.20x = - 120

x = $600

So his saving in January were  600 - 400 = $200.

answer: 42

use a calculator to find that 845/73 = 11.575

the whole part of the answer is 11. multiply this by 73 to get 11*73 = 803.

subtract that result from 845 to get 845 - 803 = 42