ANSWER:
Zach has 28 dimes and 7 quarters.
SOLUTION:
Given, Zach has 4 times as many dimes as quarters
And they have a combined value of 455 cents,
We need to find how many of each coins does he have?
Let, the number of dimes be x and number of quarters be y.
Then, x = 4y → (1)
Total combined value = 455 cents
x(value of one dime) + y(value of one quarter) = 455 cents
x(10 cents) + x(25 cents) = 455 cents
10x + 25y = 455 → (2)
Now, substitute (1) in (2)
10(4y) + 25y = 455
40x + 25y = 455
65y = 455
y = 7
substitute y value in (1)
x = 4(7) = 28
Hence, zach has 28 dimes and 7 quarters.