Answer:
They have 45 quarters and 16 nickels.
Step-by-step explanation:
Let x be the number of quarters and y be the number of nickels in the jar,
Since, the jar contains 61 coins,
⇒ x + y = 61 ------(1)
Also, 1 quart = $ 0.25 and 1 nickel = $ 0.05,
So, the total cost = ( 0.25x + 0.05y ) dollars,
According to the question,
0.25x + 0.05y = 12.05,
⇒ 25x + 5y = 1205 -----(2),
Equation (2) - 5 × Equation (1),
20x = 1205 - 305
20x = 900
⇒ x = 45,
From equation (1)m,
y = 61 - 45 = 16,
Hence, they have 45 quarters and 16 nickels.