Exercise 20 Page 717

When calculating probability, we are comparing the number of favorable outcomes to the number of possible outcomes. To calculate the probability that a randomly chosen card has a number that is not divisible by 3 we will use the Probability Formula. P=Favorable Outcomes/Possible Outcomes There is a total of 10 cards socks, which is the number of possible outcomes. 1,2, 3,4,5, 6,7,8, 9,10Out of ten cards, there are three cards divisible by 3 and seven cards that are not divisible by 3. This means that the number of favorable outcomes is 7. Now we have enough information to calculate P(divisible by3).

P=Favorable Outcomes/Possible Outcomes

SubstituteValues

Substitute values

P(divisible by3)=7/10

The probability of choosing a card with a number that is divisible by 7 is 710. Next, we can rewrite the fraction as a decimal and as a percent.

As a Decimal

To write a fraction as a decimal, we divide the numerator by the denominator.

We found that 710 expressed as a decimal is 0.7.

As a Percent

To write a fraction as a percent, we first find an equivalent fraction with a denominator of 100. 7/10=p/100 Let's solve the equation for p.

7/10 = p/100

MultEqn

LHS * 100=RHS* 100

7/10* 100 =p/100* 100

FracMultDenomToNumber

a/100* 100 = a

7/10* 100 = p

MoveRightFacToNumOne

1/b* a = a/b

700/10 = p

CalcQuot

Calculate quotient

70 = p

RearrangeEqn

Rearrange equation

p = 70

The fraction written as a percent is 70 %.