Power + percentages - practice problems
Number of problems found: 52
- Heat energy
Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1°C, 4200 J of heat energy is required. (a) Kelly wants to increase the temperature of 2 liters of w - False positive, false negative
Suppose the likelihood of someone being allergic to cats is 1/1000 of the general population. A test to determine if you're allergic to cats has a false positive rate of 5%; that is, 5% of the time, the test will indicate incorrectly that you are allergic - Cost and sell price
A wholesaler sold items at a profit of 20% of the sales, which was a profit of P52.80. What were the cost price and selling price of the item? - Simple interest 5
At what simple interest rate should Renel invest his P45,000 so that it earns P5,500 in 1 year and 5 months? - Original 83173
When drying, the modeling mass loses 36% of its original volume. If the cube's volume is 5.12 dm³ after drying, what was the original length of the edge? - Electrical 82513
How long will it take for a current of 8A in a resistance of 30 ohms to develop thermal energy of 3 MJ if the efficiency of converting electrical energy into heat is 90%? - Horsepower 81496
The electric motor has an efficiency of 80% (power and input ratio). What is the power input of this motor if its power is 5 horsepower (HP)? Enter the result in kilowatts (kW) and round to one decimal place (1 HP = 3/4 kW). - A math
A math teacher teaches Geometry and Precalculus. 37% of students take both math classes, and only 39% take just Geometry. What is the probability that a student will attend Precalculus given that they attended Geometry? What is the percentage of students - Mr. Erel
Mr. Erel earns 12% compounded quarterly. He projected to collect Ᵽ500,000 after ten years. What is the amount he needs to invest? - Distance 69524
The length of the Odra in Moravia is 42% of its length in Poland. The total flow length from the source to the sea is 1165 km. What is the distance in Moravia, and what is the distance in km on the Polish side? - Social beneficiaries
In a certain community, 52% are SAP beneficiaries, 15% are members of 4Ps, and 8% are both SAP and 4 Ps. If a citizen from the community is an SAP, what is the probability that he also is 4Ps? If that person is not a 4Ps, what is the probability that he i - The power generator
How much would be paid for the generator if it costs 2000 and 12.5% tax is charged on it? - Performance 45861
The electric motor with a power input of 25 kW works with an efficiency of 80 percent. He will do the work in 6 hours. What is the performance, and what part of the work is the loss? - Doctors
The drug successfully treats 90% of cases. Calculate the probability that it will cure at least 18 patients out of 20. - Electric cooker
During which time, does an electric cooker with power input P = 500 W and with efficiency n = 75% heat water with mass m = 2 kg and temperature t1 = 10°C to the boiling point (t2 = 100°C). The specific heat capacity of water is c = 4 180 J. Kg-1. K-1 - Quadrilateral 29201
How much sheet is needed for a roof with the shape of a regular quadrilateral pyramid if its edge is 2.8 m long and the height of the roof is 0.8 m?Calculate 10% for the overlap (extra). - Performance 20233
How many% need to increase performance, if the work we have planned for five days we have to manage in 3 days. - Transformer 20073
The transformer is oil-cooled and transforms a power of 20MW with an efficiency of 92%. Determine the temperature of the oil at the outlet of the transformer if the oil was 20°C when it entered the transformer. 2.5 liters of oil will flow through the tran - The ball
The ball has a radius of 2m. What percentage of the surface and volume is another sphere whose radius is 20% larger? - Increases 14471
How many percent will it increase a) surface b) cube volume if the edge of the cube increases by 25%?
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