According to the problem, the coins can be grouped in sets, containing 3 nickels and one dime in each set. Thus each set is worth 3*5 + 10 = 25 cents, and the number of sets is= 21. It gives the ANSWER: there are 21 dimes and 3*21 = 63 nickels. CHECK. 21*10 + 63*5 = 526 cents, in total, or $5.25. ! correct !