Percentages — Quiz 4

Questions in this quiz (5)

1. In thermodynamics, the efficiency of a heat engine is calculated by dividing the useful work the engine performs by the heat energy absorbed from burning fuel and then converting it to a percentage. If an engine performs 365 joules of useful work while absorbing 525 joules of heat from burning fuel, what is the efficiency of the engine to the nearest percent?

   • $$62%$$
   • $$70%$$
   • $$85%$$
   • $$67%$$

2. If 15% of a number $$N$$ is 450, then what number is 300% of $$N$$?

   • $$9000$$
   • $$450$$
   • $$3000$$
   • $$4500$$

3. If 30% more than a number is 520, what is 15% less than the number?

   • $$280$$
   • $$340$$
   • $$400$$
   • $$280$$

4. What single discount is equivalent to two successive discounts of 20% and 10%?

   • $$10\%$$
   • $$28\%$$
   • $$30\%$$
   • $$72\%$$

5. If 5 students, representing $$12\frac{1}{2}\%$$ of the class, failed geometry, how many students passed the course?

   • 25
   • 40
   • 35
   • 50