Grace K. answered 04/09/20
Mathematics Tutor Specializing in Algebra
If we let q represent number of quarters and d represent number of dimes, we can come up with two equations:
q + d = 95 (the total number of coins we have is 95)
0.25q + 0.10d = 15.35 (the .25 and .10 come from the monetary worth of quarters and dimes)
From there, we can solve one of the equations for one variable and substitute that in the second equation. For simplicity, let's solve the first equation for q.
By subtracting d from both sides, we end up with q = 95 - d. Let's plug that into our second equation.
0.25(95 - d) + 0.10d = 15.35
23.75 - 0.25d + 0.10d = 15.35 (distributive property)
23.75 - 0.15d = 15.35 (combine like terms)
-0.15d = -8.40 (subtract 23.75 from both sides)
d = 56 (divide both sides by -0.15)
From this we can see that we have 56 dimes. Going back to our first equation, we can then solve for how many quarters we have.
q + d = 95
q + 56 = 95
q = 39
So, we have 56 dimes and 39 quarters.
If you want to double check your work, we can see that 0.25(39) + 0.10(56) does in fact equal 15.35.