altogether there are 40 pieces of silverware in the drawer. There are twice as many spoons as there are forks and ten fewer knives then there are spoons. How many forks, spoons and knives are there?

Answer 1

Let's call the number of spoons S, the number of forks F and the number of knives K. Then we can write equations and solve them. The given facts lead to these equations: S + F + K = 40, S = 2F (thus F = S/2), and K = S - 10. Now we can rewrite the first equation in terms of only S, it becomes S + S/2 + S - 10 = 40. Combining like terms and adding 10 yields 5S/2 = 50. Now mutiply by 2/5 to get S = 20. From there it's easy to solve for K = 10 and F = 10. Thus we have 10 forks, 20 spoons and 10 knives.