Exercise 5 Page p36

To calculate the probability of picking a coin of the value less than

$ 1,

P = \frac{Number of favorable outcomes}{Number of possible outcomes}

The jar which we are choosing from contains

70

nickels,

100

dimes,

80

quarters, and

50

one-dollar coins. For the denominator of this formula, the total number of possible outcomes, we need the total number of coins.

70 + 100 + 80 + 50 = 300 coins

For the numerator of this formula, the total number of favorable outcomes, we need the total number of nickels, dimes and quarters.

70 + 100 + 80 = 250 coins

Now we have enough information to calculate

P (value less than $ 1) .

P = \frac{Number of favorable outcomes}{Number of possible outcomes}

Substitute values

P (value less than $ 1) = \frac{2 5 0}{3 0 0}

$\frac{a}{b} = \frac{a / 1 0}{b / 1 0}$

P (value less than $ 1) = \frac{2 5}{3 0}

$\frac{a}{b} = \frac{a / 5}{b / 5}$

P (value less than $ 1) = \frac{5}{6}

The probability of choosing a value less than

$ 1

\frac{5}{6} .

Hints