[Question]: Francis' family has 2 ukuleles, 4 guitars, and a certain number of violins. Each ukulele has 4 strings. Each guitar has 6 strings. Each violin has 4 strings. If the total number of strings among the ukuleles, guitars, and violins is 40 strings, how many violins does Francis' family have?
[Answer]: From the ukuleles, there are 2 * 4 = 8 strings. From the guitars, there are 4 * 6 = 24 strings. From the violins, there are 40 - 8 - 24 = 8 strings. The total number of violins Francis' family has is 8 / 4 = 2 violins.
So the answer is 2.

[Question]: An employee makes 30 dollars an hour for the first 40 hours in the workweek and an additional 50% for every hour above 40 in the week. If he works 6 hours for the first 3 days in the workweek and twice as many hours per day for the remaining 2 days, how much money did he make?
[Answer]: His overtime pay per hour is 30 * 1.5 = $45 per hour. He works 6 * 2 = 12 hours per day for the last two days. He works 6 + 6 + 6 + 12 + 12 = 42 hours. He gets 42 - 40 = 2 hours of overtime. He makes 40 * 30 + 2 * 45 = $1290 for the week.
So the answer is 1290.

[Question]: Maria wants to paint a picture and needs some tools to do that. She wants to buy a set of brushes for $20 and some canvas for three times more than the brushes. The paint costs Maria $8 per liter, and she needs at least 5 liters. How much money will she earn on the painting if she will be able to sell it for $200?
[Answer]:
Maria wants to pay 3 * 20 = $60 for the canvas. Maria needs 5 liters of paint, so the cost of it would be 8 * 5 = $40. So in total Maria will earn 200 - 40 - 60 - 20 = $80 if she will be able to sell the painting at the mentioned price.
So the answer is 80.