Wilson paints 40% of a bookcase in 20 minutes how much more time will it take him to finish the bookcase?

30 minutes

Step-by-step explanation:

He paints 40% of the bookcase in 20 minutes.

The rest of the bookcase is 100% - 40% = 60%.

60% of the bookcase still needs painting.

40% is to 20 minutes as 60% is to x minutes

40/20 = 60/x

Reduce the fraction on the left side.

2 = 60/x

Multiply both sides by x.

2x = 60

Divide both sides by 2.

x = 30

30 minutes

the inequality is:

250c+180g≥950

step-by-step explanation:

let c denotes the number of days in a week   miyoko worked as a cryptographer.

and g denotes the number of days in a week she works as a geologist.

now we are given that she earns $250 for every day she works as a cryptographer,and earns $180 for every day she works as a geologist.

now miyoko's goal is to earn more than $950 this week.

hence, the inequality could be represented as:

250c+180g≥950

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.