Question

I don’t understand this, can somebody help?

Answer 1

29)

$quarters = 13 \\ dimes = 25 \\ nickles = 18 \\ pennies = 30 \\ total \: coins = 86$

$not \: penny \: or \: dime = quarter \: or \: nickle$

$p(x) = \frac{13 + 18}{86} = \frac{31}{86} = 0.36$

30)

$gallons \: for \: car \: 1 = \frac{450}{18} = 25 \: gal$

$gallons \: for \: car \: 2 = \frac{450}{25} = 18 \: gal$

$we \: need \: 25 + 18 = 43 \: gallons$

$43 \times 2.49 = 107.07 \: dollars$