A collection of coins contains 13 pennies, 14 dimes, and 5 quarters. What is the percentage of pennies in the collection? Express your answer to two significant figures and include the appropriate units.

28. which is not a reason that water is used to store spent fuel rods from nuclear power plants? water increases the speed of the chain reaction in the fuel rods. water protects nuclear power plant workers from the high temperature and radiation of the fuel rods. water acts as a radiation shield to reduce the radiation levels. water cools the spent rods. salts action