math
posted by katy on .
How would I solve this:
Mr. Merrill has 3 times as many nickels as dimes. The coins have a total of $1.50. How many of each coin does he have?

n = 3d
5n + 10d = 150
Substitute 3d for n in second equation and solve for d. Insert that value into the first equation and solve for n. Check by inserting both values into the second equation. 
d = number of dimes
3d = number of nickels
d + 3d = 1.50
simplify and solve the equation for d and 3d 
ooops, I misread question. Sorry