Answer:
6 dimes and 18 nickels
Step-by-step explanation:
Pick two variables to represent the number of nickels and dimes Ricky has.
Let's say n = number of nickels and d = number of dimes.
Ricky has 150 cents total. Since one nickel is worth 5 cents, and one dime is worth 10 cents, their value in cents would be 5n and 10d. So, 150 = 5n + 10d.
Since Ricky has three times as many nickels as dimes, n = 3d. So, 150 = 5(3d) + 10d.
From there, you have to solve for d first.
150 = 5(3d) + 10d = 15d + 10d = 25d
150/25 = 25d/25
6 = d
Then, plug it back in for the value of n.
150 = 5n + 10(6) = 5n + 60
150 - 60 = 5n + 60 - 60
90/5 = 5n/5
18 = n
Ricky has 6 dimes and 18 nickels.