A symptom of worn piston rings is:

If 5x = 25, x equals:

Electricity is the most inefficient and costly way to heat a home. One kilowatt-hour of electricity creates about 3,400 British thermal units (BTUs). (BTUs are a standard heat measurement.) The price of electricity per kilowatt-hour is between $0.10 and $0.25 or between $29.35 and $73.13 per million BTUs.
In contrast, fuel oil, which produces 140,000 BTUs per gallon, costs about $8.33 to $13.89 per million BTUs. Natural gas, which produces 100,000 BTUs per therm, can be purchased for $5.00 to $22.50 per million BTUs. Oak firewood, which produces 26,000,000 BTUs per cord, costs $5.77 to $13.46 per million BTUs.
Choosing the right heating method for your home, based on the cost of fuel, may be more expensive at installation but will be cheaper in the long run.
The title of this passage should be:

Confident most nearly means:

What mechanical advantage does the block and tackle arrangement in the above figure give?