Robin has a collection of nickels, dimes, and quarters worth $63.50. she has 30 more dimes than nickels and twice as many quarters as dimes. how many coins of each kind does she have?

The first thing we must do is define variables:

x: number of nickels

y: number of dimes

z: number of quarters

We write the system of equations:

0.05x + 0.1y + 0.25z = 63.50

y = x + 30

z = 2y

Solving the system by substitution we have:

0.05x + 0.1 (x + 30) + 0.25 (2 (x + 30)) = 63.50

0.05x + 0.1x + 3 + 0.5x + 15 = 63.50

0.65x = 63.50 - 18

x = 45.5 / 0.65

x = 70

Then, the value of z and y is:

y = x + 30

y = 70 + 30

y = 100

On the other hand:

z = 2y

z = 2 (100)

z = 200

70 nickels

100 dimes

200 quarters

2500

step-by-step explanation:

step-by-step explanation:

we can use this expression to calculate the energy gain as a particle moves with a field or the energy loss as it moves against it. (note that it is also used to define the electron-volt, a unit of energy equal to that gained by an electron as it falls through a pd of 1 v, i.e. w = 1 ev = 1.6 10-19 c 1 v = 1.6 10-19j).in fact this expression is really nothing more than the statement that potential is the potential energy per unit charge. in this case, v= w/qis simply stating that the change in potential energy(or work done) per unit charge is equal to the change in potential (or potential difference), v.student questions: uniform electric fields2electron beamcathode+5 kvanode0 v