Luis has a change jar that contains only pennies and dimes. he has 74 coins which add up to a total of $4.61. how many of each type of coin does he have?

p +d = 74 coins

 rewrite as p =74-d

0.01p + 0.10d = 4.61

0.01(74-d) +0.10d = 4.61

0.74 - 0.01d +0.10d =4.61

0.74 +0.09d =4.61

0.09d = 3.87

d = 3.87/.09 = 43

p = 74-43 = 31

 43 dimes and 31 pennies

the answer is d. 75%

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: