Question

I have 47 nickels and dimes worth $4.20. How many of each type of coin do I have?

Answer 1

Answer:

37 dimes and 10 nickels

Step-by-step explanation:

let d = # dimes

let n = # nickels

we can set up a system of equations:

n + d = 47

.05n + .10d = 4.2

if we solve the first equation for 'n' we get:  

n = 47-d

now we can substitute this in for 'n' in the second equation:

.05(47-d) + .10d = 4.2

2.35 - .05d + .10d = 4.2

2.35 + .05d = 4.2

subtract 2.35 from each side to get:

.05d = 1.85

d = 1.85÷.05

d = 37

if d+n = 47 and d=37 then n = 10

Check:

.05(10) + .1(37) should equal 4.2

.50 + 3.7 = 4.2  [It Checks Out]