Questions in mathematics

Questions in mathematics

[Done] A machine uses 2.5 liters of fuel each hour it runs. Its fuel tank was filled with 10 liters, but 1.5 liters have already been used. How many more hours will the machine run?

[Done] The Math Club plans to pay a visitor $280 to speak at a fundraiser. Tickets will be sold for $7 each. 1. Find an equation that gives the profit/loss for the event as it varies with the number of tickets sold. 2. How many people must attend the event for the club to break even?

[Done] Solve the equation: \[ 5y - 2y = 3y + 2 \]

[Done] If I work, then I earn money, but if I'm idle, then I enjoy myself. Either I work or I'm idle. However, if I work, then I do not enjoy myself, while if I'm idle, then I do not earn money. Therefore: A. I work if and only if I enjoy myself. B. I work if I earn money. C. I do not earn money if I'm idle. D. I enjoy myself if and only if I do not earn money.

[Done] Find two numbers whose product is -140 and sum is -4.

[Done] Write an algebraic expression for two-fifths the cube of a number.

[Done] $6300 is invested, part of it at 12%, and part at 6%. For a certain year, the total yield is $564.00. How much was invested at each rate?

[Done] Luanne made a photocopy of a drawing of a rectangle. The original drawing was 4.5 inches wide and 6 inches long. The copy was 6.75 inches wide and 9 inches long. What was the scale factor for Luanne's copy?

[Done] A square and a circle have equal areas. Which shape has a shorter perimeter?

[Done] What is 2.1 rounded to the nearest tenth?