Math prob HElp. PLEASE SHOW ALL WORK WIRTH EXPLANATIONS FOR THE ANSWER?

Question

a collection of quarters and dimes is worth $6.75. the number of dimes is 4 less than 3 times the number of quarters. how many of each are there?

shoow work answer and explain

Answer 1

Let x= number of dimes

Let y= number of quarters

0.1x+0.25y= 6.75

x= 3y-4

0.1(3y-4)+0.25y= 6.75

0.3y-0.4+0.25y= 6.75

0.55y-0.4= 6.75

0.55y= 7.15

y= 13

x= 3(13)-4

x= 39-4

x= 35

35 dimes, 13 quarters