A student has 30 dimes and nickels. Their total value is $2.70. If d = number of dimes and n = number of nickels, this system of equations represents the situation:
d + n = 30
0.10d + 0.05n = 2.70
How many of each type of coin are there? Solve the system to answer the question.

A.
24 dimes and 6 nickels

B.
20 dimes and 10 nickels

C.
10 dimes and 20 nickels

D.
6 dimes and 24 nickels